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| <title>Using the GNU Compiler Collection (GCC): Symbol-Renaming Pragmas</title> |
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| <h4 class="subsection">6.59.7 Symbol-Renaming Pragmas</h4> |
| |
| <p>For compatibility with the Solaris system headers, GCC |
| supports two <code>#pragma</code> directives that change the name used in |
| assembly for a given declaration. To get this effect |
| on all platforms supported by GCC, use the asm labels extension (see <a href="Asm-Labels.html#Asm-Labels">Asm Labels</a>). |
| </p> |
| <dl compact="compact"> |
| <dt><code>redefine_extname <var>oldname</var> <var>newname</var></code></dt> |
| <dd><a name="index-pragma_002c-redefine_005fextname"></a> |
| |
| <p>This pragma gives the C function <var>oldname</var> the assembly symbol |
| <var>newname</var>. The preprocessor macro <code>__PRAGMA_REDEFINE_EXTNAME</code> |
| is defined if this pragma is available (currently on all platforms). |
| </p></dd> |
| </dl> |
| |
| <p>This pragma and the asm labels extension interact in a complicated |
| manner. Here are some corner cases you may want to be aware of. |
| </p> |
| <ol> |
| <li> Both pragmas silently apply only to declarations with external |
| linkage. Asm labels do not have this restriction. |
| |
| </li><li> In C++, both pragmas silently apply only to declarations with |
| “C” linkage. Again, asm labels do not have this restriction. |
| |
| </li><li> If any of the three ways of changing the assembly name of a |
| declaration is applied to a declaration whose assembly name has |
| already been determined (either by a previous use of one of these |
| features, or because the compiler needed the assembly name in order to |
| generate code), and the new name is different, a warning issues and |
| the name does not change. |
| |
| </li><li> The <var>oldname</var> used by <code>#pragma redefine_extname</code> is |
| always the C-language name. |
| </li></ol> |
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