AC_DEFINE_INTEGER_BITS (TYPE [, CANDIDATE-TYPE]...)
, 

2002年01月31日

Scott Pakin <pakin@uiuc.edu>

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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. Users of this software should generally follow the principles of the MIT License includings its disclaimer.

cryp.to ac-archive's Miscellaneous (released)

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

AC_DEFUN([AC_DEFINE_INTEGER_BITS],
[m4_define([ac_datatype_bits], [m4_translit(1,ドル [a-zA-Z_])])
m4_define([ac_datatype_bytes], [m4_eval(ac_datatype_bits/8)])
AC_CHECK_TYPE(1,ドル ,
 [
 AC_MSG_NOTICE([trying to find a suitable ]ac_datatype_bytes[-byte replacement for 1ドル])
 1ドル=no
 find_1ドル ()
 {
 _AC_DEFINE_INTEGER_BITS_HELPER($@)
 :
 }
 find_1ドル
 AC_DEFINE_UNQUOTED(1,ドル $1,ドル
 [If not already defined, then define as a datatype of *exactly* ]ac_datatype_bits[ bits.])
 ])
])
dnl Iterate over arguments 2ドル..$N, trying to find a good match for 1ドル.
m4_define([_AC_DEFINE_INTEGER_BITS_HELPER],
[ifelse(2,ドル , ,
 [m4_define([ac_datatype_bits], [m4_translit(1,ドル [a-zA-Z_])])
 m4_define([ac_datatype_bytes], [m4_eval(ac_datatype_bits/8)])
 AC_CHECK_SIZEOF(2ドル)
 if test "$AS_TR_SH(ac_cv_sizeof_2ドル)" -eq ac_datatype_bytes; then
 1ドル="2ドル"
 return
 fi
 _AC_DEFINE_INTEGER_BITS_HELPER(1,ドル m4_shift(m4_shift($@)))
 ])
])