gettext: AM_ICONV
13.5.6 AM_ICONV in ‘iconv.m4’
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The ‘AM_ICONV’ macro tests for the presence of the POSIX/XSI ‘iconv’
function family in either the C library or a separate ‘libiconv’
library. If found, it sets the ‘am_cv_func_iconv’ variable to ‘yes’; it
defines ‘HAVE_ICONV’ to 1 in the autoconf generated configuration file
(usually called ‘config.h’); it defines ‘ICONV_CONST’ to ‘const’ or to
empty, depending on whether the second argument of ‘iconv()’ is of type
‘const char **’ or ‘char **’; it sets the variables ‘LIBICONV’ and
‘LTLIBICONV’ to the linker options for use in a Makefile (‘LIBICONV’ for
use without libtool, ‘LTLIBICONV’ for use with libtool); it adds an ‘-I’
option to ‘CPPFLAGS’ if necessary. If not found, it sets ‘LIBICONV’ and
‘LTLIBICONV’ to empty and doesn’t change ‘CPPFLAGS’.
The complexities that ‘AM_ICONV’ deals with are the following:
• Some operating systems have ‘iconv’ in the C library, for example
glibc. Some have it in a separate library ‘libiconv’, for example
OSF/1 or FreeBSD. Regardless of the operating system, GNU
‘libiconv’ might have been installed. In that case, it should be
used instead of the operating system’s native ‘iconv’.
• GNU ‘libiconv’, if installed, is not necessarily already in the
search path (‘CPPFLAGS’ for the include file search path, ‘LDFLAGS’
for the library search path).
• GNU ‘libiconv’ is binary incompatible with some operating system’s
native ‘iconv’, for example on FreeBSD. Use of an ‘iconv.h’ and
‘libiconv.so’ that don’t fit together would produce program
crashes.
• GNU ‘libiconv’, if installed, is not necessarily already in the run
time library search path. To avoid the need for setting an
environment variable like ‘LD_LIBRARY_PATH’, the macro adds the
appropriate run time search path options to the ‘LIBICONV’
variable. This works on most systems, but not on some operating
systems with limited shared library support, like SCO.
‘iconv.m4’ is distributed with the GNU gettext package because
‘gettext.m4’ relies on it.
Info Catalog
gettext: AM_XGETTEXT_OPTION
gettext: autoconf macros