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Autoconf Macro: _ac_c_ifdef
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<h1>
_ac_c_ifdef
</h1>
<h2>
Synopsis
</h2>
<p class="indent" style="white-space:nowrap;">
<code>_AC_C_IFDEF(MACRO-NAME, ACTION-IF-DEF, ACTION-IF-NOT-DEF)</code>
</p>
<h2>
Description
</h2>
<div class="indent">
<p>
Check for the definition of macro MACRO-NAME using the current language's
compiler.
</p>
</div>
<h2>
Author
</h2>
<p class="indent">
Ludovic Courtès <ludo@chbouib.org>
</p>
<h2>
Last Modified
</h2>
<p class="indent">
2004-09-07
</p>
<h2>
M4 Source Code
</h2>
<div class="indent">
<pre class="m4source">
AC_DEFUN([_AC_C_IFDEF],
[AC_COMPILE_IFELSE([#ifndef $1
# error "Macro $1 is undefined!"
/* For some compilers (eg. SGI's CC), #error is not
enough... */
please, do fail
#endif],
[$2], [$3])])
</pre>
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<h2>
License
</h2>
<div class="indent">
<span style="white-space:nowrap;">Copyright © 2004 Ludovic
Courtès <ludo@chbouib.org></span>
<p>
Copying and distribution of this file, with or without modification, are
permitted in any medium without royalty provided the copyright notice and
this notice are preserved.
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