@node ax_check_library
@unnumberedsec ax_check_library

@majorheading Synopsis

@smallexample
AX_CHECK_LIBRARY(VARIABLE-PREFIX, HEADER-FILE, LIBRARY-FILE,
                 [ACTION-IF-FOUND], [ACTION-IF-NOT_FOUND])
@end smallexample

@majorheading Description

Provides a generic test for a given library, similar in concept to the
PKG_CHECK_MODULES macro used by pkg-config.

Most simplest libraries can be checked against simply through the
presence of a header file and a library to link to. This macro allows to
wrap around the test so that it doesn't have to be recreated each time.

Rather than define --with-$LIBRARY arguments, it uses variables in the
same way that PKG_CHECK_MODULES does. It doesn't, though, use the same
names, since you shouldn't provide a value for LIBS or CFLAGS but rather
for LDFLAGS and CPPFLAGS, to tell the linker and compiler where to find
libraries and headers respectively.

If the library is find, HAVE_PREFIX is defined, and in all cases
PREFIX_LDFLAGS and PREFIX_CPPFLAGS are substituted.

Example:

@smallexample
  AX_CHECK_LIBRARY([LIBEVENT], [event.h], [event], [],
                   [AC_MSG_ERROR([Unable to find libevent])])
@end smallexample

@majorheading Source Code

Download the
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_check_library.m4,latest
version of @file{ax_check_library.m4}} or browse
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=history;f=m4/ax_check_library.m4,the
macro's revision history}.

@majorheading License

@w{Copyright @copyright{} 2010 Diego Elio Petteno` @email{flameeyes@@gmail.com}}

This program is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.

You should have received a copy of the GNU General Public License along
with this program. If not, see <https://www.gnu.org/licenses/>.

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gives unlimited permission to copy, distribute and modify the configure
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