132 lines
3.9 KiB
Plaintext
132 lines
3.9 KiB
Plaintext
.TH RWARRAY 3am "Mar 11 2022" "Free Software Foundation" "GNU Awk Extension Modules"
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.SH NAME
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writea, reada, writeall, readall \- write and read gawk arrays to/from files
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.SH SYNOPSIS
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.ft CW
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@load "rwarray"
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.sp
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ret = writea(file, array)
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.br
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ret = reada(file, array)
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.br
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ret = writeall(file)
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.br
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ret = readall(file)
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.ft R
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.SH DESCRIPTION
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The
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.I rwarray
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extension adds functions named
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.BR writea() ,
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.BR reada() ,
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.BR writeall() ,
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and
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.BR readall() ,
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as follows.
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.TP
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.B writea()
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This function takes a string argument, which is the name of the
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file to which dump the array, and the array itself as the second
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argument.
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.B writea()
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understands multidimensional arrays.
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It returns one on success, or zero upon failure.
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.TP
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.B reada()
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is the inverse of
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.BR writea() ;
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it reads the file named as its first argument, filling in
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the array named as the second argument. It clears the array
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first.
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Here too, the return value is one on success and zero upon failure.
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.TP
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.B writeall()
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This function takes a string argument, which is the name of the
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file to which dump the state of all variables. Calling this function
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is completely equivalent to calling
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.B writea()
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with the second argument equal to
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.BR SYMTAB .
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It returns one on success, or zero upon failure.
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.TP
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.B readall()
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This function takes a string argument, which is the name of the
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file from which to read the contents of various global variables.
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For each variable in the file, the data is loaded unless the variable
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already exists. If the variable already exists, the data for that variable
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in the file is ignored.
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It returns one on success, or zero upon failure.
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.SH NOTES
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The array created by
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.B reada()
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is identical to that written by
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.B writea()
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in the sense that the contents are the same. However, due
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to implementation issues, the array traversal order of the recreated
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array will likely be different from that of the original array.
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As array traversal order in AWK is by default undefined, this is
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not (technically) a problem. If you need to guarantee a particular
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traversal order, use the array sorting features in
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.I gawk
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to do so.
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.PP
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The file contains binary data. All integral values are written
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in network byte order.
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However, double precision floating-point values are written as
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native binary data. Thus, arrays containing only string data
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can theoretically be dumped on systems with one byte order and
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restored on systems with a different one, but this has not been tried.
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.\" .SH BUGS
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.SH EXAMPLE
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.ft CW
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.nf
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@load "rwarray"
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\&...
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ret = writea("arraydump.bin", array)
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\&...
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ret = reada("arraydump.bin", array)
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\&...
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ret = writeall("globalstate.bin")
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\&...
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ret = readall("globalstate.bin")
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.fi
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.ft R
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.SH "SEE ALSO"
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.IR "GAWK: Effective AWK Programming" ,
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.IR filefuncs (3am),
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.IR fnmatch (3am),
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.IR fork (3am),
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.IR inplace (3am),
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.IR ordchr (3am),
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.IR readdir (3am),
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.IR readfile (3am),
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.IR revoutput (3am),
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.IR time (3am).
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.SH AUTHOR
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Arnold Robbins,
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.BR arnold@skeeve.com .
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.SH COPYING PERMISSIONS
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Copyright \(co 2012, 2013, 2018, 2022
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Free Software Foundation, Inc.
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.PP
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Permission is granted to make and distribute verbatim copies of
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this manual page provided the copyright notice and this permission
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notice are preserved on all copies.
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.ig
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Permission is granted to process this file through troff and print the
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results, provided the printed document carries copying permission
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notice identical to this one except for the removal of this paragraph
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(this paragraph not being relevant to the printed manual page).
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..
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.PP
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Permission is granted to copy and distribute modified versions of this
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manual page under the conditions for verbatim copying, provided that
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the entire resulting derived work is distributed under the terms of a
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permission notice identical to this one.
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.PP
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Permission is granted to copy and distribute translations of this
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manual page into another language, under the above conditions for
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modified versions, except that this permission notice may be stated in
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a translation approved by the Foundation.
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.\" vim: set filetype=nroff :
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