179 lines
7.6 KiB
HTML
179 lines
7.6 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- Copyright (C) 1988-2016 Free Software Foundation, Inc.
|
||
|
|
|
||
|
|
Permission is granted to copy, distribute and/or modify this document
|
||
|
|
under the terms of the GNU Free Documentation License, Version 1.3 or
|
||
|
|
any later version published by the Free Software Foundation; with the
|
||
|
|
Invariant Sections being "Funding Free Software", the Front-Cover
|
||
|
|
Texts being (a) (see below), and with the Back-Cover Texts being (b)
|
||
|
|
(see below). A copy of the license is included in the section entitled
|
||
|
|
"GNU Free Documentation License".
|
||
|
|
|
||
|
|
(a) The FSF's Front-Cover Text is:
|
||
|
|
|
||
|
|
A GNU Manual
|
||
|
|
|
||
|
|
(b) The FSF's Back-Cover Text is:
|
||
|
|
|
||
|
|
You have freedom to copy and modify this GNU Manual, like GNU
|
||
|
|
software. Copies published by the Free Software Foundation raise
|
||
|
|
funds for GNU development. -->
|
||
|
|
<!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<title>Using the GNU Compiler Collection (GCC): Diagnostic Pragmas</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Using the GNU Compiler Collection (GCC): Diagnostic Pragmas">
|
||
|
|
<meta name="keywords" content="Using the GNU Compiler Collection (GCC): Diagnostic Pragmas">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<link href="index.html#Top" rel="start" title="Top">
|
||
|
|
<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Pragmas.html#Pragmas" rel="up" title="Pragmas">
|
||
|
|
<link href="Visibility-Pragmas.html#Visibility-Pragmas" rel="next" title="Visibility Pragmas">
|
||
|
|
<link href="Weak-Pragmas.html#Weak-Pragmas" rel="prev" title="Weak Pragmas">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.smallquotation {font-size: smaller}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.indentedblock {margin-left: 3.2em}
|
||
|
|
div.lisp {margin-left: 3.2em}
|
||
|
|
div.smalldisplay {margin-left: 3.2em}
|
||
|
|
div.smallexample {margin-left: 3.2em}
|
||
|
|
div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
|
||
|
|
div.smalllisp {margin-left: 3.2em}
|
||
|
|
kbd {font-style:oblique}
|
||
|
|
pre.display {font-family: inherit}
|
||
|
|
pre.format {font-family: inherit}
|
||
|
|
pre.menu-comment {font-family: serif}
|
||
|
|
pre.menu-preformatted {font-family: serif}
|
||
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smallexample {font-size: smaller}
|
||
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
||
|
|
pre.smalllisp {font-size: smaller}
|
||
|
|
span.nocodebreak {white-space:nowrap}
|
||
|
|
span.nolinebreak {white-space:nowrap}
|
||
|
|
span.roman {font-family:serif; font-weight:normal}
|
||
|
|
span.sansserif {font-family:sans-serif; font-weight:normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
|
||
|
|
<a name="Diagnostic-Pragmas"></a>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Visibility-Pragmas.html#Visibility-Pragmas" accesskey="n" rel="next">Visibility Pragmas</a>, Previous: <a href="Weak-Pragmas.html#Weak-Pragmas" accesskey="p" rel="prev">Weak Pragmas</a>, Up: <a href="Pragmas.html#Pragmas" accesskey="u" rel="up">Pragmas</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<a name="Diagnostic-Pragmas-1"></a>
|
||
|
|
<h4 class="subsection">6.61.12 Diagnostic Pragmas</h4>
|
||
|
|
|
||
|
|
<p>GCC allows the user to selectively enable or disable certain types of
|
||
|
|
diagnostics, and change the kind of the diagnostic. For example, a
|
||
|
|
project’s policy might require that all sources compile with
|
||
|
|
<samp>-Werror</samp> but certain files might have exceptions allowing
|
||
|
|
specific types of warnings. Or, a project might selectively enable
|
||
|
|
diagnostics and treat them as errors depending on which preprocessor
|
||
|
|
macros are defined.
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>#pragma GCC diagnostic <var>kind</var> <var>option</var></code></dt>
|
||
|
|
<dd><a name="index-pragma_002c-diagnostic"></a>
|
||
|
|
|
||
|
|
<p>Modifies the disposition of a diagnostic. Note that not all
|
||
|
|
diagnostics are modifiable; at the moment only warnings (normally
|
||
|
|
controlled by ‘<samp>-W…</samp>’) can be controlled, and not all of them.
|
||
|
|
Use <samp>-fdiagnostics-show-option</samp> to determine which diagnostics
|
||
|
|
are controllable and which option controls them.
|
||
|
|
</p>
|
||
|
|
<p><var>kind</var> is ‘<samp>error</samp>’ to treat this diagnostic as an error,
|
||
|
|
‘<samp>warning</samp>’ to treat it like a warning (even if <samp>-Werror</samp> is
|
||
|
|
in effect), or ‘<samp>ignored</samp>’ if the diagnostic is to be ignored.
|
||
|
|
<var>option</var> is a double quoted string that matches the command-line
|
||
|
|
option.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">#pragma GCC diagnostic warning "-Wformat"
|
||
|
|
#pragma GCC diagnostic error "-Wformat"
|
||
|
|
#pragma GCC diagnostic ignored "-Wformat"
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>Note that these pragmas override any command-line options. GCC keeps
|
||
|
|
track of the location of each pragma, and issues diagnostics according
|
||
|
|
to the state as of that point in the source file. Thus, pragmas occurring
|
||
|
|
after a line do not affect diagnostics caused by that line.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
<dt><code>#pragma GCC diagnostic push</code></dt>
|
||
|
|
<dt><code>#pragma GCC diagnostic pop</code></dt>
|
||
|
|
<dd>
|
||
|
|
<p>Causes GCC to remember the state of the diagnostics as of each
|
||
|
|
<code>push</code>, and restore to that point at each <code>pop</code>. If a
|
||
|
|
<code>pop</code> has no matching <code>push</code>, the command-line options are
|
||
|
|
restored.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">#pragma GCC diagnostic error "-Wuninitialized"
|
||
|
|
foo(a); /* error is given for this one */
|
||
|
|
#pragma GCC diagnostic push
|
||
|
|
#pragma GCC diagnostic ignored "-Wuninitialized"
|
||
|
|
foo(b); /* no diagnostic for this one */
|
||
|
|
#pragma GCC diagnostic pop
|
||
|
|
foo(c); /* error is given for this one */
|
||
|
|
#pragma GCC diagnostic pop
|
||
|
|
foo(d); /* depends on command-line options */
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<p>GCC also offers a simple mechanism for printing messages during
|
||
|
|
compilation.
|
||
|
|
</p>
|
||
|
|
<dl compact="compact">
|
||
|
|
<dt><code>#pragma message <var>string</var></code></dt>
|
||
|
|
<dd><a name="index-pragma_002c-diagnostic-1"></a>
|
||
|
|
|
||
|
|
<p>Prints <var>string</var> as a compiler message on compilation. The message
|
||
|
|
is informational only, and is neither a compilation warning nor an error.
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">#pragma message "Compiling " __FILE__ "..."
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p><var>string</var> may be parenthesized, and is printed with location
|
||
|
|
information. For example,
|
||
|
|
</p>
|
||
|
|
<div class="smallexample">
|
||
|
|
<pre class="smallexample">#define DO_PRAGMA(x) _Pragma (#x)
|
||
|
|
#define TODO(x) DO_PRAGMA(message ("TODO - " #x))
|
||
|
|
|
||
|
|
TODO(Remember to fix this)
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>prints ‘<samp>/tmp/file.c:4: note: #pragma message:
|
||
|
|
TODO - Remember to fix this</samp>’.
|
||
|
|
</p>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
<div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Visibility-Pragmas.html#Visibility-Pragmas" accesskey="n" rel="next">Visibility Pragmas</a>, Previous: <a href="Weak-Pragmas.html#Weak-Pragmas" accesskey="p" rel="prev">Weak Pragmas</a>, Up: <a href="Pragmas.html#Pragmas" accesskey="u" rel="up">Pragmas</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|