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Diffstat (limited to 'm4/ac_define_integer_bits.m4')
| -rw-r--r-- | m4/ac_define_integer_bits.m4 | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/m4/ac_define_integer_bits.m4 b/m4/ac_define_integer_bits.m4 new file mode 100644 index 0000000..431d769 --- /dev/null +++ b/m4/ac_define_integer_bits.m4 @@ -0,0 +1,76 @@ +# =========================================================================== +# http://autoconf-archive.cryp.to/ac_define_integer_bits.html +# =========================================================================== +# +# SYNOPSIS +# +# AC_DEFINE_INTEGER_BITS (TYPE [, CANDIDATE-TYPE]...) +# +# 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: +# +# AC_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 +# +# You should then put the following in your C code to ensure that all +# datatypes defined by AC_DEFINE_INTEGER_BITS are visible to your program: +# +# #include "config.h" +# +# #if HAVE_INTTYPES_H +# # include <inttypes.h> +# #else +# # if HAVE_STDINT_H +# # include <stdint.h> +# # endif +# #endif +# +# LICENSE +# +# Copyright (c) 2008 Scott Pakin <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. + +AC_DEFUN([AC_DEFINE_INTEGER_BITS], +[m4_define([ac_datatype_bits], [m4_translit($1, [a-zA-Z_])]) +m4_define([ac_datatype_bytes], [m4_eval(ac_datatype_bits/8)]) +AC_CHECK_TYPE($1, , + [ + AC_MSG_NOTICE([trying to find a suitable ]ac_datatype_bytes[-byte replacement for $1]) + $1=no + find_$1 () + { + _AC_DEFINE_INTEGER_BITS_HELPER($@) + : + } + find_$1 + AC_DEFINE_UNQUOTED($1, $$1, + [If not already defined, then define as a datatype of *exactly* ]ac_datatype_bits[ bits.]) + ]) +]) + +dnl Iterate over arguments $2..$N, trying to find a good match for $1. +m4_define([_AC_DEFINE_INTEGER_BITS_HELPER], +[ifelse($2, , , + [m4_define([ac_datatype_bits], [m4_translit($1, [a-zA-Z_])]) + m4_define([ac_datatype_bytes], [m4_eval(ac_datatype_bits/8)]) + AC_CHECK_SIZEOF($2) + if test "$AS_TR_SH(ac_cv_sizeof_$2)" -eq ac_datatype_bytes; then + $1="$2" + return + fi + _AC_DEFINE_INTEGER_BITS_HELPER($1, m4_shift(m4_shift($@))) + ]) +]) |