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@node ax_define_integer_bits
@unnumberedsec ax_define_integer_bits
@majorheading Synopsis
@smallexample
AX_DEFINE_INTEGER_BITS (TYPE [, CANDIDATE-TYPE]...)
@end smallexample
@majorheading Description
Given a TYPE of the form "int##_t" or "uint##_t", see if the datatype
TYPE is predefined. If not, then define TYPE -- both with AC_DEFINE and
as a shell variable -- to the first datatype of exactly ## bits in a
list of CANDIDATE-TYPEs. If none of the CANDIDATE-TYPEs contains exactly
## bits, then set the TYPE shell variable to "no".
For example, the following ensures that uint64_t is defined as a 64-bit
datatype:
@smallexample
AX_DEFINE_INTEGER_BITS(uint64_t, unsigned long long, unsigned __int64, long)
if test "$uint64_t" = no; then
AC_MSG_ERROR([unable to continue without a 64-bit datatype])
fi
@end smallexample
You should then put the following in your C code to ensure that all
datatypes defined by AX_DEFINE_INTEGER_BITS are visible to your program:
@smallexample
#include "config.h"
@end smallexample
@smallexample
#if HAVE_INTTYPES_H
# include <inttypes.h>
#else
# if HAVE_STDINT_H
# include <stdint.h>
# endif
#endif
@end smallexample
@majorheading Source Code
Download the
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=blob_plain;f=m4/ax_define_integer_bits.m4,latest
version of @file{ax_define_integer_bits.m4}} or browse
@uref{http://git.savannah.gnu.org/gitweb/?p=autoconf-archive.git;a=history;f=m4/ax_define_integer_bits.m4,the
macro's revision history}.
@majorheading License
@w{Copyright @copyright{} 2008 Scott Pakin @email{pakin@@uiuc.edu}}
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. This file is offered as-is, without any
warranty.
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