1322 lines
53 KiB
Plaintext
1322 lines
53 KiB
Plaintext
@node Argp, Suboptions, Getopt, Parsing Program Arguments
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@need 5000
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@section Parsing Program Options with Argp
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@cindex argp (program argument parser)
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@cindex argument parsing with argp
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@cindex option parsing with argp
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@dfn{Argp} is an interface for parsing unix-style argument vectors.
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@xref{Program Arguments}.
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Argp provides features unavailable in the more commonly used
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@code{getopt} interface. These features include automatically producing
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output in response to the @samp{--help} and @samp{--version} options, as
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described in the GNU coding standards. Using argp makes it less likely
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that programmers will neglect to implement these additional options or
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keep them up to date.
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Argp also provides the ability to merge several independently defined
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option parsers into one, mediating conflicts between them and making the
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result appear seamless. A library can export an argp option parser that
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user programs might employ in conjunction with their own option parsers,
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resulting in less work for the user programs. Some programs may use only
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argument parsers exported by libraries, thereby achieving consistent and
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efficient option-parsing for abstractions implemented by the libraries.
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@pindex argp.h
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The header file @file{<argp.h>} should be included to use argp.
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@subsection The @code{argp_parse} Function
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The main interface to argp is the @code{argp_parse} function. In many
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cases, calling @code{argp_parse} is the only argument-parsing code
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needed in @code{main}.
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@xref{Program Arguments}.
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@deftypefun {error_t} argp_parse (const struct argp *@var{argp}, int @var{argc}, char **@var{argv}, unsigned @var{flags}, int *@var{arg_index}, void *@var{input})
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@standards{GNU, argp.h}
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@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtslocale{} @mtsenv{}}@asunsafe{@ascuheap{} @ascuintl{} @asulock{} @asucorrupt{}}@acunsafe{@acsmem{} @aculock{} @acucorrupt{}}}
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@c Optionally alloca()tes standard help options, initializes the parser,
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@c then parses individual args in a loop, and then finalizes.
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@c parser_init
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@c calc_sizes ok
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@c option_is_end ok
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@c malloc @ascuheap @acsmem
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@c parser_convert @mtslocale
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@c convert_options @mtslocale
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@c option_is_end ok
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@c option_is_short ok
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@c isprint, but locale may change within the loop
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@c find_long_option ok
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@c group_parse
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@c group->parser (from argp->parser)
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@c parser_parse_next
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@c getopt_long(_only)_r many issues, same as non_r minus @mtasurace
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@c parser_parse_arg
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@c group_parse dup
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@c parser_parse_opt
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@c group_parse dup
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@c argp_error dup @mtasurace:argpbuf @mtsenv @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
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@c dgettext (bad key error) dup @mtsenv @asucorrupt @ascuheap @asulock @ascudlopen @acucorrupt @aculock @acsfd @acsmem
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@c parser_finalize
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@c group_parse
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@c fprintf dup @mtslocale @asucorrupt @aculock @acucorrupt [no @ascuheap @acsmem]
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@c dgettext dup @mtsenv @asucorrupt @ascuheap @asulock @ascudlopen @acucorrupt @aculock @acsfd @acsmem
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@c arg_state_help
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@c free dup @ascuhelp @acsmem
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The @code{argp_parse} function parses the arguments in @var{argv}, of
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length @var{argc}, using the argp parser @var{argp}. @xref{Argp
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Parsers}. Passing a null pointer for @var{argp} is the same as using
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a @code{struct argp} containing all zeros.
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@var{flags} is a set of flag bits that modify the parsing behavior.
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@xref{Argp Flags}. @var{input} is passed through to the argp parser
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@var{argp}, and has meaning defined by @var{argp}. A typical usage is
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to pass a pointer to a structure which is used for specifying
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parameters to the parser and passing back the results.
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Unless the @code{ARGP_NO_EXIT} or @code{ARGP_NO_HELP} flags are included
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in @var{flags}, calling @code{argp_parse} may result in the program
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exiting. This behavior is true if an error is detected, or when an
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unknown option is encountered. @xref{Program Termination}.
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If @var{arg_index} is non-null, the index of the first unparsed option
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in @var{argv} is returned as a value.
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The return value is zero for successful parsing, or an error code
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(@pxref{Error Codes}) if an error is detected. Different argp parsers
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may return arbitrary error codes, but the standard error codes are:
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@code{ENOMEM} if a memory allocation error occurred, or @code{EINVAL} if
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an unknown option or option argument is encountered.
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@end deftypefun
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@menu
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* Globals: Argp Global Variables. Global argp parameters.
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* Parsers: Argp Parsers. Defining parsers for use with @code{argp_parse}.
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* Flags: Argp Flags. Flags that modify the behavior of @code{argp_parse}.
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* Help: Argp Help. Printing help messages when not parsing.
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* Examples: Argp Examples. Simple examples of programs using argp.
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* Customization: Argp User Customization.
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Users may control the @samp{--help} output format.
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@end menu
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@node Argp Global Variables, Argp Parsers, , Argp
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@subsection Argp Global Variables
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These variables make it easy for user programs to implement the
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@samp{--version} option and provide a bug-reporting address in the
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@samp{--help} output. These are implemented in argp by default.
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@deftypevar {const char *} argp_program_version
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@standards{GNU, argp.h}
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If defined or set by the user program to a non-zero value, then a
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@samp{--version} option is added when parsing with @code{argp_parse},
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which will print the @samp{--version} string followed by a newline and
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exit. The exception to this is if the @code{ARGP_NO_EXIT} flag is used.
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@end deftypevar
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@deftypevar {const char *} argp_program_bug_address
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@standards{GNU, argp.h}
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If defined or set by the user program to a non-zero value,
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@code{argp_program_bug_address} should point to a string that will be
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printed at the end of the standard output for the @samp{--help} option,
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embedded in a sentence that says @samp{Report bugs to @var{address}.}.
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@end deftypevar
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@need 1500
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@defvar argp_program_version_hook
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@standards{GNU, argp.h}
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If defined or set by the user program to a non-zero value, a
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@samp{--version} option is added when parsing with @code{arg_parse},
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which prints the program version and exits with a status of zero. This
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is not the case if the @code{ARGP_NO_HELP} flag is used. If the
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@code{ARGP_NO_EXIT} flag is set, the exit behavior of the program is
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suppressed or modified, as when the argp parser is going to be used by
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other programs.
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It should point to a function with this type of signature:
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@smallexample
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void @var{print-version} (FILE *@var{stream}, struct argp_state *@var{state})
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@end smallexample
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@noindent
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@xref{Argp Parsing State}, for an explanation of @var{state}.
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This variable takes precedence over @code{argp_program_version}, and is
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useful if a program has version information not easily expressed in a
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simple string.
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@end defvar
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@deftypevar error_t argp_err_exit_status
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@standards{GNU, argp.h}
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This is the exit status used when argp exits due to a parsing error. If
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not defined or set by the user program, this defaults to:
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@code{EX_USAGE} from @file{<sysexits.h>}.
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@end deftypevar
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@node Argp Parsers, Argp Flags, Argp Global Variables, Argp
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@subsection Specifying Argp Parsers
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The first argument to the @code{argp_parse} function is a pointer to a
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@code{struct argp}, which is known as an @dfn{argp parser}:
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@deftp {Data Type} {struct argp}
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@standards{GNU, argp.h}
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This structure specifies how to parse a given set of options and
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arguments, perhaps in conjunction with other argp parsers. It has the
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following fields:
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@table @code
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@item const struct argp_option *options
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A pointer to a vector of @code{argp_option} structures specifying which
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options this argp parser understands; it may be zero if there are no
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options at all. @xref{Argp Option Vectors}.
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@item argp_parser_t parser
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A pointer to a function that defines actions for this parser; it is
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called for each option parsed, and at other well-defined points in the
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parsing process. A value of zero is the same as a pointer to a function
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that always returns @code{ARGP_ERR_UNKNOWN}. @xref{Argp Parser
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Functions}.
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@item const char *args_doc
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If non-zero, a string describing what non-option arguments are called by
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this parser. This is only used to print the @samp{Usage:} message. If
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it contains newlines, the strings separated by them are considered
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alternative usage patterns and printed on separate lines. Lines after
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the first are prefixed by @samp{ or: } instead of @samp{Usage:}.
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@item const char *doc
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If non-zero, a string containing extra text to be printed before and
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after the options in a long help message, with the two sections
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separated by a vertical tab (@code{'\v'}, @code{'\013'}) character. By
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convention, the documentation before the options is just a short string
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explaining what the program does. Documentation printed after the
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options describe behavior in more detail.
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@item const struct argp_child *children
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A pointer to a vector of @code{argp_child} structures. This pointer
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specifies which additional argp parsers should be combined with this
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one. @xref{Argp Children}.
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@item char *(*help_filter)(int @var{key}, const char *@var{text}, void *@var{input})
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If non-zero, a pointer to a function that filters the output of help
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messages. @xref{Argp Help Filtering}.
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@item const char *argp_domain
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If non-zero, the strings used in the argp library are translated using
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the domain described by this string. If zero, the current default domain
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is used.
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@end table
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@end deftp
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Of the above group, @code{options}, @code{parser}, @code{args_doc}, and
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the @code{doc} fields are usually all that are needed. If an argp
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parser is defined as an initialized C variable, only the fields used
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need be specified in the initializer. The rest will default to zero due
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to the way C structure initialization works. This design is exploited in
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most argp structures; the most-used fields are grouped near the
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beginning, the unused fields left unspecified.
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@menu
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* Options: Argp Option Vectors. Specifying options in an argp parser.
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* Argp Parser Functions:: Defining actions for an argp parser.
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* Children: Argp Children. Combining multiple argp parsers.
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* Help Filtering: Argp Help Filtering. Customizing help output for an argp parser.
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@end menu
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@node Argp Option Vectors, Argp Parser Functions, Argp Parsers, Argp Parsers
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@subsection Specifying Options in an Argp Parser
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The @code{options} field in a @code{struct argp} points to a vector of
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@code{struct argp_option} structures, each of which specifies an option
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that the argp parser supports. Multiple entries may be used for a single
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option provided it has multiple names. This should be terminated by an
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entry with zero in all fields. Note that when using an initialized C
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array for options, writing @code{@{ 0 @}} is enough to achieve this.
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@deftp {Data Type} {struct argp_option}
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@standards{GNU, argp.h}
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This structure specifies a single option that an argp parser
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understands, as well as how to parse and document that option. It has
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the following fields:
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@table @code
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@item const char *name
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The long name for this option, corresponding to the long option
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@samp{--@var{name}}; this field may be zero if this option @emph{only}
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has a short name. To specify multiple names for an option, additional
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entries may follow this one, with the @code{OPTION_ALIAS} flag
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set. @xref{Argp Option Flags}.
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@item int key
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The integer key provided by the current option to the option parser. If
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@var{key} has a value that is a printable @sc{ascii} character (i.e.,
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@code{isascii (@var{key})} is true), it @emph{also} specifies a short
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option @samp{-@var{char}}, where @var{char} is the @sc{ascii} character
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with the code @var{key}.
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@item const char *arg
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If non-zero, this is the name of an argument associated with this
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option, which must be provided (e.g., with the
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@samp{--@var{name}=@var{value}} or @samp{-@var{char} @var{value}}
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syntaxes), unless the @code{OPTION_ARG_OPTIONAL} flag (@pxref{Argp
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Option Flags}) is set, in which case it @emph{may} be provided.
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@item int flags
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Flags associated with this option, some of which are referred to above.
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@xref{Argp Option Flags}.
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@item const char *doc
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A documentation string for this option, for printing in help messages.
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If both the @code{name} and @code{key} fields are zero, this string
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will be printed tabbed left from the normal option column, making it
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useful as a group header. This will be the first thing printed in its
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group. In this usage, it's conventional to end the string with a
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@samp{:} character.
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@item int group
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Group identity for this option.
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In a long help message, options are sorted alphabetically within each
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group, and the groups presented in the order 0, 1, 2, @dots{}, @var{n},
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@minus{}@var{m}, @dots{}, @minus{}2, @minus{}1.
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Every entry in an options array with this field 0 will inherit the group
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number of the previous entry, or zero if it's the first one. If it's a
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group header with @code{name} and @code{key} fields both zero, the
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previous entry + 1 is the default. Automagic options such as
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@samp{--help} are put into group @minus{}1.
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Note that because of C structure initialization rules, this field often
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need not be specified, because 0 is the correct value.
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@end table
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@end deftp
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@menu
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* Flags: Argp Option Flags. Flags for options.
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@end menu
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@node Argp Option Flags, , , Argp Option Vectors
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@subsubsection Flags for Argp Options
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The following flags may be or'd together in the @code{flags} field of a
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@code{struct argp_option}. These flags control various aspects of how
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that option is parsed or displayed in help messages:
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@vtable @code
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@item OPTION_ARG_OPTIONAL
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@standards{GNU, argp.h}
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The argument associated with this option is optional.
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@item OPTION_HIDDEN
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@standards{GNU, argp.h}
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This option isn't displayed in any help messages.
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@item OPTION_ALIAS
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@standards{GNU, argp.h}
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This option is an alias for the closest previous non-alias option. This
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means that it will be displayed in the same help entry, and will inherit
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fields other than @code{name} and @code{key} from the option being
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aliased.
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@item OPTION_DOC
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@standards{GNU, argp.h}
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This option isn't actually an option and should be ignored by the actual
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option parser. It is an arbitrary section of documentation that should
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be displayed in much the same manner as the options. This is known as a
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@dfn{documentation option}.
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If this flag is set, then the option @code{name} field is displayed
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unmodified (e.g., no @samp{--} prefix is added) at the left-margin where
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a @emph{short} option would normally be displayed, and this
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documentation string is left in its usual place. For purposes of
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sorting, any leading whitespace and punctuation is ignored, unless the
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first non-whitespace character is @samp{-}. This entry is displayed
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after all options, after @code{OPTION_DOC} entries with a leading
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@samp{-}, in the same group.
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@item OPTION_NO_USAGE
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@standards{GNU, argp.h}
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This option shouldn't be included in `long' usage messages, but should
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still be included in other help messages. This is intended for options
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that are completely documented in an argp's @code{args_doc}
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field. @xref{Argp Parsers}. Including this option in the generic usage
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list would be redundant, and should be avoided.
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For instance, if @code{args_doc} is @code{"FOO BAR\n-x BLAH"}, and the
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@samp{-x} option's purpose is to distinguish these two cases, @samp{-x}
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should probably be marked @code{OPTION_NO_USAGE}.
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@end vtable
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@node Argp Parser Functions, Argp Children, Argp Option Vectors, Argp Parsers
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@subsection Argp Parser Functions
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The function pointed to by the @code{parser} field in a @code{struct
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argp} (@pxref{Argp Parsers}) defines what actions take place in response
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to each option or argument parsed. It is also used as a hook, allowing a
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parser to perform tasks at certain other points during parsing.
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@need 2000
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Argp parser functions have the following type signature:
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@cindex argp parser functions
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@smallexample
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error_t @var{parser} (int @var{key}, char *@var{arg}, struct argp_state *@var{state})
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@end smallexample
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@noindent
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where the arguments are as follows:
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@table @var
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@item key
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For each option that is parsed, @var{parser} is called with a value of
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@var{key} from that option's @code{key} field in the option
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vector. @xref{Argp Option Vectors}. @var{parser} is also called at
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other times with special reserved keys, such as @code{ARGP_KEY_ARG} for
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non-option arguments. @xref{Argp Special Keys}.
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@item arg
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If @var{key} is an option, @var{arg} is its given value. This defaults
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to zero if no value is specified. Only options that have a non-zero
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@code{arg} field can ever have a value. These must @emph{always} have a
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value unless the @code{OPTION_ARG_OPTIONAL} flag is specified. If the
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input being parsed specifies a value for an option that doesn't allow
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one, an error results before @var{parser} ever gets called.
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If @var{key} is @code{ARGP_KEY_ARG}, @var{arg} is a non-option
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argument. Other special keys always have a zero @var{arg}.
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@item state
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@var{state} points to a @code{struct argp_state}, containing useful
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information about the current parsing state for use by
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@var{parser}. @xref{Argp Parsing State}.
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@end table
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When @var{parser} is called, it should perform whatever action is
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appropriate for @var{key}, and return @code{0} for success,
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@code{ARGP_ERR_UNKNOWN} if the value of @var{key} is not handled by this
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parser function, or a unix error code if a real error
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occurred. @xref{Error Codes}.
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@deftypevr Macro int ARGP_ERR_UNKNOWN
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@standards{GNU, argp.h}
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Argp parser functions should return @code{ARGP_ERR_UNKNOWN} for any
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@var{key} value they do not recognize, or for non-option arguments
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(@code{@var{key} == ARGP_KEY_ARG}) that they are not equipped to handle.
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@end deftypevr
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@need 3000
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A typical parser function uses a switch statement on @var{key}:
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@smallexample
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error_t
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parse_opt (int key, char *arg, struct argp_state *state)
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@{
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switch (key)
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@{
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case @var{option_key}:
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@var{action}
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break;
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@dots{}
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default:
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return ARGP_ERR_UNKNOWN;
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@}
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return 0;
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@}
|
|
@end smallexample
|
|
|
|
@menu
|
|
* Keys: Argp Special Keys. Special values for the @var{key} argument.
|
|
* State: Argp Parsing State. What the @var{state} argument refers to.
|
|
* Functions: Argp Helper Functions. Functions to help during argp parsing.
|
|
@end menu
|
|
|
|
@node Argp Special Keys, Argp Parsing State, , Argp Parser Functions
|
|
@subsubsection Special Keys for Argp Parser Functions
|
|
|
|
In addition to key values corresponding to user options, the @var{key}
|
|
argument to argp parser functions may have a number of other special
|
|
values. In the following example @var{arg} and @var{state} refer to
|
|
parser function arguments. @xref{Argp Parser Functions}.
|
|
|
|
@vtable @code
|
|
@item ARGP_KEY_ARG
|
|
@standards{GNU, argp.h}
|
|
This is not an option at all, but rather a command line argument, whose
|
|
value is pointed to by @var{arg}.
|
|
|
|
When there are multiple parser functions in play due to argp parsers
|
|
being combined, it's impossible to know which one will handle a specific
|
|
argument. Each is called until one returns 0 or an error other than
|
|
@code{ARGP_ERR_UNKNOWN}; if an argument is not handled,
|
|
@code{argp_parse} immediately returns success, without parsing any more
|
|
arguments.
|
|
|
|
Once a parser function returns success for this key, that fact is
|
|
recorded, and the @code{ARGP_KEY_NO_ARGS} case won't be
|
|
used. @emph{However}, if while processing the argument a parser function
|
|
decrements the @code{next} field of its @var{state} argument, the option
|
|
won't be considered processed; this is to allow you to actually modify
|
|
the argument, perhaps into an option, and have it processed again.
|
|
|
|
@item ARGP_KEY_ARGS
|
|
@standards{GNU, argp.h}
|
|
If a parser function returns @code{ARGP_ERR_UNKNOWN} for
|
|
@code{ARGP_KEY_ARG}, it is immediately called again with the key
|
|
@code{ARGP_KEY_ARGS}, which has a similar meaning, but is slightly more
|
|
convenient for consuming all remaining arguments. @var{arg} is 0, and
|
|
the tail of the argument vector may be found at @code{@var{state}->argv
|
|
+ @var{state}->next}. If success is returned for this key, and
|
|
@code{@var{state}->next} is unchanged, all remaining arguments are
|
|
considered to have been consumed. Otherwise, the amount by which
|
|
@code{@var{state}->next} has been adjusted indicates how many were used.
|
|
Here's an example that uses both, for different args:
|
|
|
|
|
|
@smallexample
|
|
@dots{}
|
|
case ARGP_KEY_ARG:
|
|
if (@var{state}->arg_num == 0)
|
|
/* First argument */
|
|
first_arg = @var{arg};
|
|
else
|
|
/* Let the next case parse it. */
|
|
return ARGP_KEY_UNKNOWN;
|
|
break;
|
|
case ARGP_KEY_ARGS:
|
|
remaining_args = @var{state}->argv + @var{state}->next;
|
|
num_remaining_args = @var{state}->argc - @var{state}->next;
|
|
break;
|
|
@end smallexample
|
|
|
|
@item ARGP_KEY_END
|
|
@standards{GNU, argp.h}
|
|
This indicates that there are no more command line arguments. Parser
|
|
functions are called in a different order, children first. This allows
|
|
each parser to clean up its state for the parent.
|
|
|
|
@item ARGP_KEY_NO_ARGS
|
|
@standards{GNU, argp.h}
|
|
Because it's common to do some special processing if there aren't any
|
|
non-option args, parser functions are called with this key if they
|
|
didn't successfully process any non-option arguments. This is called
|
|
just before @code{ARGP_KEY_END}, where more general validity checks on
|
|
previously parsed arguments take place.
|
|
|
|
@item ARGP_KEY_INIT
|
|
@standards{GNU, argp.h}
|
|
This is passed in before any parsing is done. Afterwards, the values of
|
|
each element of the @code{child_input} field of @var{state}, if any, are
|
|
copied to each child's state to be the initial value of the @code{input}
|
|
when @emph{their} parsers are called.
|
|
|
|
@item ARGP_KEY_SUCCESS
|
|
@standards{GNU, argp.h}
|
|
Passed in when parsing has successfully been completed, even if
|
|
arguments remain.
|
|
|
|
@item ARGP_KEY_ERROR
|
|
@standards{GNU, argp.h}
|
|
Passed in if an error has occurred and parsing is terminated. In this
|
|
case a call with a key of @code{ARGP_KEY_SUCCESS} is never made.
|
|
|
|
@item ARGP_KEY_FINI
|
|
@standards{GNU, argp.h}
|
|
The final key ever seen by any parser, even after
|
|
@code{ARGP_KEY_SUCCESS} and @code{ARGP_KEY_ERROR}. Any resources
|
|
allocated by @code{ARGP_KEY_INIT} may be freed here. At times, certain
|
|
resources allocated are to be returned to the caller after a successful
|
|
parse. In that case, those particular resources can be freed in the
|
|
@code{ARGP_KEY_ERROR} case.
|
|
@end vtable
|
|
|
|
In all cases, @code{ARGP_KEY_INIT} is the first key seen by parser
|
|
functions, and @code{ARGP_KEY_FINI} the last, unless an error was
|
|
returned by the parser for @code{ARGP_KEY_INIT}. Other keys can occur
|
|
in one the following orders. @var{opt} refers to an arbitrary option
|
|
key:
|
|
|
|
@table @asis
|
|
@item @var{opt}@dots{} @code{ARGP_KEY_NO_ARGS} @code{ARGP_KEY_END} @code{ARGP_KEY_SUCCESS}
|
|
The arguments being parsed did not contain any non-option arguments.
|
|
|
|
@item ( @var{opt} | @code{ARGP_KEY_ARG} )@dots{} @code{ARGP_KEY_END} @code{ARGP_KEY_SUCCESS}
|
|
All non-option arguments were successfully handled by a parser
|
|
function. There may be multiple parser functions if multiple argp
|
|
parsers were combined.
|
|
|
|
@item ( @var{opt} | @code{ARGP_KEY_ARG} )@dots{} @code{ARGP_KEY_SUCCESS}
|
|
Some non-option argument went unrecognized.
|
|
|
|
This occurs when every parser function returns @code{ARGP_KEY_UNKNOWN}
|
|
for an argument, in which case parsing stops at that argument if
|
|
@var{arg_index} is a null pointer. Otherwise an error occurs.
|
|
@end table
|
|
|
|
In all cases, if a non-null value for @var{arg_index} gets passed to
|
|
@code{argp_parse}, the index of the first unparsed command-line argument
|
|
is passed back in that value.
|
|
|
|
If an error occurs and is either detected by argp or because a parser
|
|
function returned an error value, each parser is called with
|
|
@code{ARGP_KEY_ERROR}. No further calls are made, except the final call
|
|
with @code{ARGP_KEY_FINI}.
|
|
|
|
@node Argp Parsing State, Argp Helper Functions, Argp Special Keys, Argp Parser Functions
|
|
@subsubsection Argp Parsing State
|
|
|
|
The third argument to argp parser functions (@pxref{Argp Parser
|
|
Functions}) is a pointer to a @code{struct argp_state}, which contains
|
|
information about the state of the option parsing.
|
|
|
|
@deftp {Data Type} {struct argp_state}
|
|
@standards{GNU, argp.h}
|
|
This structure has the following fields, which may be modified as noted:
|
|
|
|
@table @code
|
|
@item const struct argp *const root_argp
|
|
The top level argp parser being parsed. Note that this is often
|
|
@emph{not} the same @code{struct argp} passed into @code{argp_parse} by
|
|
the invoking program. @xref{Argp}. It is an internal argp parser that
|
|
contains options implemented by @code{argp_parse} itself, such as
|
|
@samp{--help}.
|
|
|
|
@item int argc
|
|
@itemx char **argv
|
|
The argument vector being parsed. This may be modified.
|
|
|
|
@item int next
|
|
The index in @code{argv} of the next argument to be parsed. This may be
|
|
modified.
|
|
|
|
One way to consume all remaining arguments in the input is to set
|
|
@code{@var{state}->next = @var{state}->argc}, perhaps after recording
|
|
the value of the @code{next} field to find the consumed arguments. The
|
|
current option can be re-parsed immediately by decrementing this field,
|
|
then modifying @code{@var{state}->argv[@var{state}->next]} to reflect
|
|
the option that should be reexamined.
|
|
|
|
@item unsigned flags
|
|
The flags supplied to @code{argp_parse}. These may be modified, although
|
|
some flags may only take effect when @code{argp_parse} is first
|
|
invoked. @xref{Argp Flags}.
|
|
|
|
@item unsigned arg_num
|
|
While calling a parsing function with the @var{key} argument
|
|
@code{ARGP_KEY_ARG}, this represents the number of the current arg,
|
|
starting at 0. It is incremented after each @code{ARGP_KEY_ARG} call
|
|
returns. At all other times, this is the number of @code{ARGP_KEY_ARG}
|
|
arguments that have been processed.
|
|
|
|
@item int quoted
|
|
If non-zero, the index in @code{argv} of the first argument following a
|
|
special @samp{--} argument. This prevents anything that follows from
|
|
being interpreted as an option. It is only set after argument parsing
|
|
has proceeded past this point.
|
|
|
|
@item void *input
|
|
An arbitrary pointer passed in from the caller of @code{argp_parse}, in
|
|
the @var{input} argument.
|
|
|
|
@item void **child_inputs
|
|
These are values that will be passed to child parsers. This vector will
|
|
be the same length as the number of children in the current parser. Each
|
|
child parser will be given the value of
|
|
@code{@var{state}->child_inputs[@var{i}]} as @emph{its}
|
|
@code{@var{state}->input} field, where @var{i} is the index of the child
|
|
in the this parser's @code{children} field. @xref{Argp Children}.
|
|
|
|
@item void *hook
|
|
For the parser function's use. Initialized to 0, but otherwise ignored
|
|
by argp.
|
|
|
|
@item char *name
|
|
The name used when printing messages. This is initialized to
|
|
@code{argv[0]}, or @code{program_invocation_name} if @code{argv[0]} is
|
|
unavailable.
|
|
|
|
@item FILE *err_stream
|
|
@itemx FILE *out_stream
|
|
The stdio streams used when argp prints. Error messages are printed to
|
|
@code{err_stream}, all other output, such as @samp{--help} output) to
|
|
@code{out_stream}. These are initialized to @code{stderr} and
|
|
@code{stdout} respectively. @xref{Standard Streams}.
|
|
|
|
@item void *pstate
|
|
Private, for use by the argp implementation.
|
|
@end table
|
|
@end deftp
|
|
|
|
@node Argp Helper Functions, , Argp Parsing State, Argp Parser Functions
|
|
@subsubsection Functions For Use in Argp Parsers
|
|
|
|
Argp provides a number of functions available to the user of argp
|
|
(@pxref{Argp Parser Functions}), mostly for producing error messages.
|
|
These take as their first argument the @var{state} argument to the
|
|
parser function. @xref{Argp Parsing State}.
|
|
|
|
|
|
@cindex usage messages, in argp
|
|
@deftypefun void argp_usage (const struct argp_state *@var{state})
|
|
@standards{GNU, argp.h}
|
|
@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}}
|
|
@c Just calls argp_state_help with stderr and ARGP_HELP_STD_USAGE.
|
|
Outputs the standard usage message for the argp parser referred to by
|
|
@var{state} to @code{@var{state}->err_stream} and terminates the program
|
|
with @code{exit (argp_err_exit_status)}. @xref{Argp Global Variables}.
|
|
@end deftypefun
|
|
|
|
@cindex syntax error messages, in argp
|
|
@deftypefun void argp_error (const struct argp_state *@var{state}, const char *@var{fmt}, @dots{})
|
|
@standards{GNU, argp.h}
|
|
@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}}
|
|
@c Lock stream, vasprintf the formatted message into a buffer, print the
|
|
@c buffer prefixed by the short program name (in libc,
|
|
@c argp_short_program_name is a macro that expands to
|
|
@c program_invocation_short_name), releases the buffer, then call
|
|
@c argp_state_help with stream and ARGP_HELP_STD_ERR, unlocking the
|
|
@c stream at the end.
|
|
Prints the printf format string @var{fmt} and following args, preceded
|
|
by the program name and @samp{:}, and followed by a @w{@samp{Try @dots{}
|
|
--help}} message, and terminates the program with an exit status of
|
|
@code{argp_err_exit_status}. @xref{Argp Global Variables}.
|
|
@end deftypefun
|
|
|
|
@cindex error messages, in argp
|
|
@deftypefun void argp_failure (const struct argp_state *@var{state}, int @var{status}, int @var{errnum}, const char *@var{fmt}, @dots{})
|
|
@standards{GNU, argp.h}
|
|
@safety{@prelim{}@mtsafe{}@asunsafe{@asucorrupt{} @ascuheap{}}@acunsafe{@aculock{} @acucorrupt{} @acsmem{}}}
|
|
@c Lock stream, write out the short program name, vasprintf the optional
|
|
@c formatted message to a buffer, print the buffer prefixed by colon and
|
|
@c blank, release the buffer, call strerror_r with an automatic buffer,
|
|
@c print it out after colon and blank, put[w]c a line break, unlock the
|
|
@c stream, then exit unless ARGP_NO_EXIT.
|
|
Similar to the standard GNU error-reporting function @code{error}, this
|
|
prints the program name and @samp{:}, the printf format string
|
|
@var{fmt}, and the appropriate following args. If it is non-zero, the
|
|
standard unix error text for @var{errnum} is printed. If @var{status} is
|
|
non-zero, it terminates the program with that value as its exit status.
|
|
|
|
The difference between @code{argp_failure} and @code{argp_error} is that
|
|
@code{argp_error} is for @emph{parsing errors}, whereas
|
|
@code{argp_failure} is for other problems that occur during parsing but
|
|
don't reflect a syntactic problem with the input, such as illegal values
|
|
for options, bad phase of the moon, etc.
|
|
@end deftypefun
|
|
|
|
@deftypefun void argp_state_help (const struct argp_state *@var{state}, FILE *@var{stream}, unsigned @var{flags})
|
|
@standards{GNU, argp.h}
|
|
@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}}
|
|
@c Just calls _help with the short program name and optionally exit.
|
|
@c The main problems in _help, besides the usual issues with stream I/O
|
|
@c and translation, are the use of a static buffer (uparams, thus
|
|
@c @mtasurace:argpbuf) that makes the whole thing thread-unsafe, reading
|
|
@c from the environment for ARGP_HELP_FMT, accessing the locale object
|
|
@c multiple times.
|
|
|
|
@c _help @mtsenv @mtasurace:argpbuf @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c dgettext @ascuintl
|
|
@c flockfile @aculock
|
|
@c funlockfile @aculock
|
|
@c fill_in_uparams @mtsenv @mtasurace:argpbuf @mtslocale @asucorrupt @ascuheap @aculock @acucorrupt @acsmem
|
|
@c argp_failure dup (status = errnum = 0)
|
|
@c atoi dup @mtslocale
|
|
@c argp_hol @ascuheap @acsmem
|
|
@c make_hol @ascuheap @acsmem
|
|
@c hol_add_cluster @ascuheap @acsmem
|
|
@c hol_append @ascuheap @acsmem
|
|
@c hol_set_group ok
|
|
@c hol_find_entry ok
|
|
@c hol_sort @mtslocale @acucorrupt
|
|
@c qsort dup @acucorrupt
|
|
@c hol_entry_qcmp @mtslocale
|
|
@c hol_entry_cmp @mtslocale
|
|
@c group_cmp ok
|
|
@c hol_cluster_cmp ok
|
|
@c group_cmp ok
|
|
@c hol_entry_first_short @mtslocale
|
|
@c hol_entry_short_iterate [@mtslocale]
|
|
@c until_short ok
|
|
@c oshort ok
|
|
@c isprint ok
|
|
@c odoc ok
|
|
@c hol_entry_first_long ok
|
|
@c canon_doc_option @mtslocale
|
|
@c tolower dup
|
|
@c hol_usage @mtslocale @ascuintl @ascuheap @acsmem
|
|
@c hol_entry_short_iterate ok
|
|
@c add_argless_short_opt ok
|
|
@c argp_fmtstream_printf dup
|
|
@c hol_entry_short_iterate @mtslocale @ascuintl @ascuheap @acsmem
|
|
@c usage_argful_short_opt @mtslocale @ascuintl @ascuheap @acsmem
|
|
@c dgettext dup
|
|
@c argp_fmtstream_printf dup
|
|
@c hol_entry_long_iterate @mtslocale @ascuintl @ascuheap @acsmem
|
|
@c usage_long_opt @mtslocale @ascuintl @ascuheap @acsmem
|
|
@c dgettext dup
|
|
@c argp_fmtstream_printf dup
|
|
@c hol_help @mtslocale @mtasurace:argpbuf @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c hol_entry_help @mtslocale @mtasurace:argpbuf @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_set_lmargin dup
|
|
@c argp_fmtstream_wmargin dup
|
|
@c argp_fmtstream_set_wmargin dup
|
|
@c comma @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_putc dup
|
|
@c hol_cluster_is_child ok
|
|
@c argp_fmtstream_wmargin dup
|
|
@c print_header dup
|
|
@c argp_fmtstream_set_wmargin dup
|
|
@c argp_fmtstream_puts dup
|
|
@c indent_to dup
|
|
@c argp_fmtstream_putc dup
|
|
@c arg @mtslocale @ascuheap @acsmem
|
|
@c argp_fmtstream_printf dup
|
|
@c odoc dup
|
|
@c argp_fmtstream_puts dup
|
|
@c argp_fmtstream_printf dup
|
|
@c print_header @mtslocale @mtasurace:argpbuf @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c dgettext dup
|
|
@c filter_doc dup
|
|
@c argp_fmtstream_putc dup
|
|
@c indent_to dup
|
|
@c argp_fmtstream_set_lmargin dup
|
|
@c argp_fmtstream_set_wmargin dup
|
|
@c argp_fmtstream_puts dup
|
|
@c free dup
|
|
@c filter_doc dup
|
|
@c argp_fmtstream_point dup
|
|
@c indent_to @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_point dup
|
|
@c argp_fmtstream_putc dup
|
|
@c dgettext dup
|
|
@c filter_doc dup
|
|
@c argp_fmtstream_putc dup
|
|
@c argp_fmtstream_puts dup
|
|
@c free dup
|
|
@c hol_free @ascuheap @acsmem
|
|
@c free dup
|
|
@c argp_args_levels ok
|
|
@c argp_args_usage @mtslocale @ascuintl @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c dgettext dup
|
|
@c filter_doc ok
|
|
@c argp_input ok
|
|
@c argp->help_filter
|
|
@c space @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_point dup
|
|
@c argp_fmtstream_rmargin @mtslocale @asucorrupt @acucorrupt @aculock
|
|
@c argp_fmtstream_update dup
|
|
@c argp_fmtstream_putc dup
|
|
@c argp_fmtstream_write dup
|
|
@c free dup
|
|
@c argp_doc @mtslocale @ascuheap @ascuintl @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c dgettext @ascuintl
|
|
@c strndup @ascuheap @acsmem
|
|
@c argp_input dup
|
|
@c argp->help_filter
|
|
@c argp_fmtstream_putc @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_ensure dup
|
|
@c argp_fmtstream_write dup
|
|
@c argp_fmtstream_puts dup
|
|
@c argp_fmtstream_point @mtslocale @asucorrupt @acucorrupt @aculock
|
|
@c argp_fmtstream_update dup
|
|
@c argp_fmtstream_lmargin dup
|
|
@c free dup
|
|
@c argp_make_fmtstream @ascuheap @acsmem
|
|
@c argp_fmtstream_free @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_update @mtslocale @asucorrupt @acucorrupt @aculock
|
|
@c put[w]c_unlocked dup
|
|
@c isblank in loop @mtslocale
|
|
@c fxprintf @aculock
|
|
@c fxprintf @aculock
|
|
@c free dup
|
|
@c argp_fmtstream_set_wmargin @mtslocale @asucorrupt @acucorrupt @aculock
|
|
@c argp_fmtstream_update dup
|
|
@c argp_fmtstream_printf @mtslocale @ascuheap @acsmem
|
|
@c argp_fmtstream_ensure dup
|
|
@c vsnprintf dup
|
|
@c argp_fmtstream_set_lmargin @mtslocale @asucorrupt @acucorrupt @aculock
|
|
@c argp_fmtstream_update dup
|
|
@c argp_fmtstream_puts @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_write @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_ensure @mtslocale @ascuheap @asucorrupt @acsmem @acucorrupt @aculock
|
|
@c argp_fmtstream_update dup
|
|
@c fxprintf @aculock
|
|
@c realloc @ascuheap @acsmem
|
|
Outputs a help message for the argp parser referred to by @var{state},
|
|
to @var{stream}. The @var{flags} argument determines what sort of help
|
|
message is produced. @xref{Argp Help Flags}.
|
|
@end deftypefun
|
|
|
|
Error output is sent to @code{@var{state}->err_stream}, and the program
|
|
name printed is @code{@var{state}->name}.
|
|
|
|
The output or program termination behavior of these functions may be
|
|
suppressed if the @code{ARGP_NO_EXIT} or @code{ARGP_NO_ERRS} flags are
|
|
passed to @code{argp_parse}. @xref{Argp Flags}.
|
|
|
|
This behavior is useful if an argp parser is exported for use by other
|
|
programs (e.g., by a library), and may be used in a context where it is
|
|
not desirable to terminate the program in response to parsing errors. In
|
|
argp parsers intended for such general use, and for the case where the
|
|
program @emph{doesn't} terminate, calls to any of these functions should
|
|
be followed by code that returns the appropriate error code:
|
|
|
|
@smallexample
|
|
if (@var{bad argument syntax})
|
|
@{
|
|
argp_usage (@var{state});
|
|
return EINVAL;
|
|
@}
|
|
@end smallexample
|
|
|
|
@noindent
|
|
If a parser function will @emph{only} be used when @code{ARGP_NO_EXIT}
|
|
is not set, the return may be omitted.
|
|
|
|
@node Argp Children, Argp Help Filtering, Argp Parser Functions, Argp Parsers
|
|
@subsection Combining Multiple Argp Parsers
|
|
|
|
The @code{children} field in a @code{struct argp} enables other argp
|
|
parsers to be combined with the referencing one for the parsing of a
|
|
single set of arguments. This field should point to a vector of
|
|
@code{struct argp_child}, which is terminated by an entry having a value
|
|
of zero in the @code{argp} field.
|
|
|
|
Where conflicts between combined parsers arise, as when two specify an
|
|
option with the same name, the parser conflicts are resolved in favor of
|
|
the parent argp parser(s), or the earlier of the argp parsers in the
|
|
list of children.
|
|
|
|
@deftp {Data Type} {struct argp_child}
|
|
@standards{GNU, argp.h}
|
|
An entry in the list of subsidiary argp parsers pointed to by the
|
|
@code{children} field in a @code{struct argp}. The fields are as
|
|
follows:
|
|
|
|
@table @code
|
|
@item const struct argp *argp
|
|
The child argp parser, or zero to end of the list.
|
|
|
|
@item int flags
|
|
Flags for this child.
|
|
|
|
@item const char *header
|
|
If non-zero, this is an optional header to be printed within help output
|
|
before the child options. As a side-effect, a non-zero value forces the
|
|
child options to be grouped together. To achieve this effect without
|
|
actually printing a header string, use a value of @code{""}. As with
|
|
header strings specified in an option entry, the conventional value of
|
|
the last character is @samp{:}. @xref{Argp Option Vectors}.
|
|
|
|
@item int group
|
|
This is where the child options are grouped relative to the other
|
|
`consolidated' options in the parent argp parser. The values are the
|
|
same as the @code{group} field in @code{struct argp_option}. @xref{Argp
|
|
Option Vectors}. All child-groupings follow parent options at a
|
|
particular group level. If both this field and @code{header} are zero,
|
|
then the child's options aren't grouped together, they are merged with
|
|
parent options at the parent option group level.
|
|
|
|
@end table
|
|
@end deftp
|
|
|
|
@node Argp Flags, Argp Help, Argp Parsers, Argp
|
|
@subsection Flags for @code{argp_parse}
|
|
|
|
The default behavior of @code{argp_parse} is designed to be convenient
|
|
for the most common case of parsing program command line argument. To
|
|
modify these defaults, the following flags may be or'd together in the
|
|
@var{flags} argument to @code{argp_parse}:
|
|
|
|
@vtable @code
|
|
@item ARGP_PARSE_ARGV0
|
|
@standards{GNU, argp.h}
|
|
Don't ignore the first element of the @var{argv} argument to
|
|
@code{argp_parse}. Unless @code{ARGP_NO_ERRS} is set, the first element
|
|
of the argument vector is skipped for option parsing purposes, as it
|
|
corresponds to the program name in a command line.
|
|
|
|
@item ARGP_NO_ERRS
|
|
@standards{GNU, argp.h}
|
|
Don't print error messages for unknown options to @code{stderr}; unless
|
|
this flag is set, @code{ARGP_PARSE_ARGV0} is ignored, as @code{argv[0]}
|
|
is used as the program name in the error messages. This flag implies
|
|
@code{ARGP_NO_EXIT}. This is based on the assumption that silent exiting
|
|
upon errors is bad behavior.
|
|
|
|
@item ARGP_NO_ARGS
|
|
@standards{GNU, argp.h}
|
|
Don't parse any non-option args. Normally these are parsed by calling
|
|
the parse functions with a key of @code{ARGP_KEY_ARG}, the actual
|
|
argument being the value. This flag needn't normally be set, as the
|
|
default behavior is to stop parsing as soon as an argument fails to be
|
|
parsed. @xref{Argp Parser Functions}.
|
|
|
|
@item ARGP_IN_ORDER
|
|
@standards{GNU, argp.h}
|
|
Parse options and arguments in the same order they occur on the command
|
|
line. Normally they're rearranged so that all options come first.
|
|
|
|
@item ARGP_NO_HELP
|
|
@standards{GNU, argp.h}
|
|
Don't provide the standard long option @samp{--help}, which ordinarily
|
|
causes usage and option help information to be output to @code{stdout}
|
|
and @code{exit (0)}.
|
|
|
|
@item ARGP_NO_EXIT
|
|
@standards{GNU, argp.h}
|
|
Don't exit on errors, although they may still result in error messages.
|
|
|
|
@item ARGP_LONG_ONLY
|
|
@standards{GNU, argp.h}
|
|
Use the GNU getopt `long-only' rules for parsing arguments. This allows
|
|
long-options to be recognized with only a single @samp{-}
|
|
(i.e., @samp{-help}). This results in a less useful interface, and its
|
|
use is discouraged as it conflicts with the way most GNU programs work
|
|
as well as the GNU coding standards.
|
|
|
|
@item ARGP_SILENT
|
|
@standards{GNU, argp.h}
|
|
Turns off any message-printing/exiting options, specifically
|
|
@code{ARGP_NO_EXIT}, @code{ARGP_NO_ERRS}, and @code{ARGP_NO_HELP}.
|
|
@end vtable
|
|
|
|
@node Argp Help Filtering, , Argp Children, Argp Parsers
|
|
@need 2000
|
|
@subsection Customizing Argp Help Output
|
|
|
|
The @code{help_filter} field in a @code{struct argp} is a pointer to a
|
|
function that filters the text of help messages before displaying
|
|
them. They have a function signature like:
|
|
|
|
@smallexample
|
|
char *@var{help-filter} (int @var{key}, const char *@var{text}, void *@var{input})
|
|
@end smallexample
|
|
|
|
|
|
@noindent
|
|
Where @var{key} is either a key from an option, in which case @var{text}
|
|
is that option's help text. @xref{Argp Option Vectors}. Alternately, one
|
|
of the special keys with names beginning with @samp{ARGP_KEY_HELP_}
|
|
might be used, describing which other help text @var{text} will contain.
|
|
@xref{Argp Help Filter Keys}.
|
|
|
|
The function should return either @var{text} if it remains as-is, or a
|
|
replacement string allocated using @code{malloc}. This will be either be
|
|
freed by argp or zero, which prints nothing. The value of @var{text} is
|
|
supplied @emph{after} any translation has been done, so if any of the
|
|
replacement text needs translation, it will be done by the filter
|
|
function. @var{input} is either the input supplied to @code{argp_parse}
|
|
or it is zero, if @code{argp_help} was called directly by the user.
|
|
|
|
@menu
|
|
* Keys: Argp Help Filter Keys. Special @var{key} values for help filter functions.
|
|
@end menu
|
|
|
|
@node Argp Help Filter Keys, , , Argp Help Filtering
|
|
@subsubsection Special Keys for Argp Help Filter Functions
|
|
|
|
The following special values may be passed to an argp help filter
|
|
function as the first argument in addition to key values for user
|
|
options. They specify which help text the @var{text} argument contains:
|
|
|
|
@vtable @code
|
|
@item ARGP_KEY_HELP_PRE_DOC
|
|
@standards{GNU, argp.h}
|
|
The help text preceding options.
|
|
|
|
@item ARGP_KEY_HELP_POST_DOC
|
|
@standards{GNU, argp.h}
|
|
The help text following options.
|
|
|
|
@item ARGP_KEY_HELP_HEADER
|
|
@standards{GNU, argp.h}
|
|
The option header string.
|
|
|
|
@item ARGP_KEY_HELP_EXTRA
|
|
@standards{GNU, argp.h}
|
|
This is used after all other documentation; @var{text} is zero for this key.
|
|
|
|
@item ARGP_KEY_HELP_DUP_ARGS_NOTE
|
|
@standards{GNU, argp.h}
|
|
The explanatory note printed when duplicate option arguments have been suppressed.
|
|
|
|
@item ARGP_KEY_HELP_ARGS_DOC
|
|
@standards{GNU, argp.h}
|
|
The argument doc string; formally the @code{args_doc} field from the argp parser. @xref{Argp Parsers}.
|
|
@end vtable
|
|
|
|
@node Argp Help, Argp Examples, Argp Flags, Argp
|
|
@subsection The @code{argp_help} Function
|
|
|
|
Normally programs using argp need not be written with particular
|
|
printing argument-usage-type help messages in mind as the standard
|
|
@samp{--help} option is handled automatically by argp. Typical error
|
|
cases can be handled using @code{argp_usage} and
|
|
@code{argp_error}. @xref{Argp Helper Functions}. However, if it's
|
|
desirable to print a help message in some context other than parsing the
|
|
program options, argp offers the @code{argp_help} interface.
|
|
|
|
@deftypefun void argp_help (const struct argp *@var{argp}, FILE *@var{stream}, unsigned @var{flags}, char *@var{name})
|
|
@standards{GNU, argp.h}
|
|
@safety{@prelim{}@mtunsafe{@mtasurace{:argpbuf} @mtsenv{} @mtslocale{}}@asunsafe{@ascuheap{} @ascuintl{} @asucorrupt{}}@acunsafe{@acsmem{} @acucorrupt{} @aculock{}}}
|
|
@c Just calls _help.
|
|
This outputs a help message for the argp parser @var{argp} to
|
|
@var{stream}. The type of messages printed will be determined by
|
|
@var{flags}.
|
|
|
|
Any options such as @samp{--help} that are implemented automatically by
|
|
argp itself will @emph{not} be present in the help output; for this
|
|
reason it is best to use @code{argp_state_help} if calling from within
|
|
an argp parser function. @xref{Argp Helper Functions}.
|
|
@end deftypefun
|
|
|
|
@menu
|
|
* Flags: Argp Help Flags. Specifying what sort of help message to print.
|
|
@end menu
|
|
|
|
@node Argp Help Flags, , , Argp Help
|
|
@subsection Flags for the @code{argp_help} Function
|
|
|
|
When calling @code{argp_help} (@pxref{Argp Help}) or
|
|
@code{argp_state_help} (@pxref{Argp Helper Functions}) the exact output
|
|
is determined by the @var{flags} argument. This should consist of any of
|
|
the following flags, or'd together:
|
|
|
|
@vtable @code
|
|
@item ARGP_HELP_USAGE
|
|
@standards{GNU, argp.h}
|
|
A unix @samp{Usage:} message that explicitly lists all options.
|
|
|
|
@item ARGP_HELP_SHORT_USAGE
|
|
@standards{GNU, argp.h}
|
|
A unix @samp{Usage:} message that displays an appropriate placeholder to
|
|
indicate where the options go; useful for showing the non-option
|
|
argument syntax.
|
|
|
|
@item ARGP_HELP_SEE
|
|
@standards{GNU, argp.h}
|
|
A @samp{Try @dots{} for more help} message; @samp{@dots{}} contains the
|
|
program name and @samp{--help}.
|
|
|
|
@item ARGP_HELP_LONG
|
|
@standards{GNU, argp.h}
|
|
A verbose option help message that gives each option available along
|
|
with its documentation string.
|
|
|
|
@item ARGP_HELP_PRE_DOC
|
|
@standards{GNU, argp.h}
|
|
The part of the argp parser doc string preceding the verbose option help.
|
|
|
|
@item ARGP_HELP_POST_DOC
|
|
@standards{GNU, argp.h}
|
|
The part of the argp parser doc string that following the verbose option help.
|
|
|
|
@item ARGP_HELP_DOC
|
|
@standards{GNU, argp.h}
|
|
@code{(ARGP_HELP_PRE_DOC | ARGP_HELP_POST_DOC)}
|
|
|
|
@item ARGP_HELP_BUG_ADDR
|
|
@standards{GNU, argp.h}
|
|
A message that prints where to report bugs for this program, if the
|
|
@code{argp_program_bug_address} variable contains this information.
|
|
|
|
@item ARGP_HELP_LONG_ONLY
|
|
@standards{GNU, argp.h}
|
|
This will modify any output to reflect the @code{ARGP_LONG_ONLY} mode.
|
|
@end vtable
|
|
|
|
The following flags are only understood when used with
|
|
@code{argp_state_help}. They control whether the function returns after
|
|
printing its output, or terminates the program:
|
|
|
|
@vtable @code
|
|
@item ARGP_HELP_EXIT_ERR
|
|
@standards{GNU, argp.h}
|
|
This will terminate the program with @code{exit (argp_err_exit_status)}.
|
|
|
|
@item ARGP_HELP_EXIT_OK
|
|
@standards{GNU, argp.h}
|
|
This will terminate the program with @code{exit (0)}.
|
|
@end vtable
|
|
|
|
The following flags are combinations of the basic flags for printing
|
|
standard messages:
|
|
|
|
@vtable @code
|
|
@item ARGP_HELP_STD_ERR
|
|
@standards{GNU, argp.h}
|
|
Assuming that an error message for a parsing error has printed, this
|
|
prints a message on how to get help, and terminates the program with an
|
|
error.
|
|
|
|
@item ARGP_HELP_STD_USAGE
|
|
@standards{GNU, argp.h}
|
|
This prints a standard usage message and terminates the program with an
|
|
error. This is used when no other specific error messages are
|
|
appropriate or available.
|
|
|
|
@item ARGP_HELP_STD_HELP
|
|
@standards{GNU, argp.h}
|
|
This prints the standard response for a @samp{--help} option, and
|
|
terminates the program successfully.
|
|
@end vtable
|
|
|
|
@node Argp Examples, Argp User Customization, Argp Help, Argp
|
|
@subsection Argp Examples
|
|
|
|
These example programs demonstrate the basic usage of argp.
|
|
|
|
@menu
|
|
* 1: Argp Example 1. A minimal program using argp.
|
|
* 2: Argp Example 2. A program using only default options.
|
|
* 3: Argp Example 3. A simple program with user options.
|
|
* 4: Argp Example 4. Combining multiple argp parsers.
|
|
@end menu
|
|
|
|
@node Argp Example 1, Argp Example 2, , Argp Examples
|
|
@subsubsection A Minimal Program Using Argp
|
|
|
|
This is perhaps the smallest program possible that uses argp. It won't
|
|
do much except give an error message and exit when there are any
|
|
arguments, and prints a rather pointless message for @samp{--help}.
|
|
|
|
@smallexample
|
|
@include argp-ex1.c.texi
|
|
@end smallexample
|
|
|
|
@node Argp Example 2, Argp Example 3, Argp Example 1, Argp Examples
|
|
@subsubsection A Program Using Argp with Only Default Options
|
|
|
|
This program doesn't use any options or arguments, it uses argp to be
|
|
compliant with the GNU standard command line format.
|
|
|
|
In addition to giving no arguments and implementing a @samp{--help}
|
|
option, this example has a @samp{--version} option, which will put the
|
|
given documentation string and bug address in the @samp{--help} output,
|
|
as per GNU standards.
|
|
|
|
The variable @code{argp} contains the argument parser
|
|
specification. Adding fields to this structure is the way most
|
|
parameters are passed to @code{argp_parse}. The first three fields are
|
|
normally used, but they are not in this small program. There are also
|
|
two global variables that argp can use defined here,
|
|
@code{argp_program_version} and @code{argp_program_bug_address}. They
|
|
are considered global variables because they will almost always be
|
|
constant for a given program, even if they use different argument
|
|
parsers for various tasks.
|
|
|
|
@smallexample
|
|
@include argp-ex2.c.texi
|
|
@end smallexample
|
|
|
|
@node Argp Example 3, Argp Example 4, Argp Example 2, Argp Examples
|
|
@subsubsection A Program Using Argp with User Options
|
|
|
|
This program uses the same features as example 2, adding user options
|
|
and arguments.
|
|
|
|
We now use the first four fields in @code{argp} (@pxref{Argp Parsers})
|
|
and specify @code{parse_opt} as the parser function. @xref{Argp Parser
|
|
Functions}.
|
|
|
|
Note that in this example, @code{main} uses a structure to communicate
|
|
with the @code{parse_opt} function, a pointer to which it passes in the
|
|
@code{input} argument to @code{argp_parse}. @xref{Argp}. It is retrieved
|
|
by @code{parse_opt} through the @code{input} field in its @code{state}
|
|
argument. @xref{Argp Parsing State}. Of course, it's also possible to
|
|
use global variables instead, but using a structure like this is
|
|
somewhat more flexible and clean.
|
|
|
|
@smallexample
|
|
@include argp-ex3.c.texi
|
|
@end smallexample
|
|
|
|
@node Argp Example 4, , Argp Example 3, Argp Examples
|
|
@subsubsection A Program Using Multiple Combined Argp Parsers
|
|
|
|
This program uses the same features as example 3, but has more options,
|
|
and presents more structure in the @samp{--help} output. It also
|
|
illustrates how you can `steal' the remainder of the input arguments
|
|
past a certain point for programs that accept a list of items. It also
|
|
illustrates the @var{key} value @code{ARGP_KEY_NO_ARGS}, which is only
|
|
given if no non-option arguments were supplied to the
|
|
program. @xref{Argp Special Keys}.
|
|
|
|
For structuring help output, two features are used: @emph{headers} and a
|
|
two part option string. The @emph{headers} are entries in the options
|
|
vector. @xref{Argp Option Vectors}. The first four fields are zero. The
|
|
two part documentation string are in the variable @code{doc}, which
|
|
allows documentation both before and after the options. @xref{Argp
|
|
Parsers}, the two parts of @code{doc} are separated by a vertical-tab
|
|
character (@code{'\v'}, or @code{'\013'}). By convention, the
|
|
documentation before the options is a short string stating what the
|
|
program does, and after any options it is longer, describing the
|
|
behavior in more detail. All documentation strings are automatically
|
|
filled for output, although newlines may be included to force a line
|
|
break at a particular point. In addition, documentation strings are
|
|
passed to the @code{gettext} function, for possible translation into the
|
|
current locale.
|
|
|
|
@smallexample
|
|
@include argp-ex4.c.texi
|
|
@end smallexample
|
|
|
|
@node Argp User Customization, , Argp Examples, Argp
|
|
@subsection Argp User Customization
|
|
|
|
@cindex ARGP_HELP_FMT environment variable
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The formatting of argp @samp{--help} output may be controlled to some
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extent by a program's users, by setting the @code{ARGP_HELP_FMT}
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environment variable to a comma-separated list of tokens. Whitespace is
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ignored:
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@table @samp
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@item dup-args
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@itemx no-dup-args
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These turn @dfn{duplicate-argument-mode} on or off. In duplicate
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argument mode, if an option that accepts an argument has multiple names,
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the argument is shown for each name. Otherwise, it is only shown for the
|
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first long option. A note is subsequently printed so the user knows that
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it applies to other names as well. The default is @samp{no-dup-args},
|
|
which is less consistent, but prettier.
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|
|
|
@item dup-args-note
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|
@item no-dup-args-note
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|
These will enable or disable the note informing the user of suppressed
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|
option argument duplication. The default is @samp{dup-args-note}.
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|
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@item short-opt-col=@var{n}
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This prints the first short option in column @var{n}. The default is 2.
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@item long-opt-col=@var{n}
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|
This prints the first long option in column @var{n}. The default is 6.
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|
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@item doc-opt-col=@var{n}
|
|
This prints `documentation options' (@pxref{Argp Option Flags}) in
|
|
column @var{n}. The default is 2.
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|
|
|
@item opt-doc-col=@var{n}
|
|
This prints the documentation for options starting in column
|
|
@var{n}. The default is 29.
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|
|
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@item header-col=@var{n}
|
|
This will indent the group headers that document groups of options to
|
|
column @var{n}. The default is 1.
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|
|
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@item usage-indent=@var{n}
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|
This will indent continuation lines in @samp{Usage:} messages to column
|
|
@var{n}. The default is 12.
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|
|
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@item rmargin=@var{n}
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|
This will word wrap help output at or before column @var{n}. The default
|
|
is 79.
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@end table
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