Mercurial > gnulib
view m4/isinf.m4 @ 40177:dcd889592b62
dtoastr,ftoastr,ldtoastr: port to c-strtod changes
Decouple these modules from c-strtod. Nowadays it’s reasonable to
assume the C99 signatures for strtod and strtold. Programs that
require stricter adherence to C99 should also use the strtod and
strtold modules as needed, and we no longer need the
HAVE_C99_STRTOLD macro.
* NEWS: Mention this.
* lib/ftoastr.c (STRTOF) [LENGTH == 3]: Assume strtold.
* m4/c-strtod.m4 (gl_C_STRTOLD): Do not define HAVE_C99_STRTOLD.
* modules/dtoastr, modules/ftoastr, modules/ldtoastr:
(Files): Remove m4/c-strtod.m4.
(configure.ac): Do not require gl_C99_STRTOLD, which no longer
exists.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Sat, 02 Feb 2019 13:01:55 -0800 |
parents | b06060465f09 |
children |
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# isinf.m4 serial 12 dnl Copyright (C) 2007-2019 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. AC_DEFUN([gl_ISINF], [ AC_REQUIRE([gl_MATH_H_DEFAULTS]) dnl Persuade glibc <math.h> to declare isinf. AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) AC_CHECK_DECLS([isinf], , , [[#include <math.h> #ifndef isinf #error "isinf must be a macro, not a function" #endif ]]) if test "$ac_cv_have_decl_isinf" = yes; then gl_CHECK_MATH_LIB([ISINF_LIBM], [x = isinf (x) + isinf ((float) x);]) if test "$ISINF_LIBM" != missing; then dnl Test whether isinf() on 'long double' works. gl_ISINFL_WORKS case "$gl_cv_func_isinfl_works" in *yes) ;; *) ISINF_LIBM=missing;; esac fi fi if test "$ac_cv_have_decl_isinf" != yes || test "$ISINF_LIBM" = missing; then REPLACE_ISINF=1 dnl No libraries are needed to link lib/isinf.c. ISINF_LIBM= fi AC_SUBST([ISINF_LIBM]) ]) dnl Test whether isinf() works: dnl 1) Whether it correctly returns false for LDBL_MAX. dnl 2) Whether on 'long double' recognizes all canonical values which are dnl infinite. AC_DEFUN([gl_ISINFL_WORKS], [ AC_REQUIRE([AC_PROG_CC]) AC_REQUIRE([gl_BIGENDIAN]) AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE]) AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles AC_CACHE_CHECK([whether isinf(long double) works], [gl_cv_func_isinfl_works], [ AC_RUN_IFELSE( [AC_LANG_SOURCE([[ #include <float.h> #include <limits.h> #include <math.h> #define NWORDS \ ((sizeof (long double) + sizeof (unsigned int) - 1) / sizeof (unsigned int)) typedef union { unsigned int word[NWORDS]; long double value; } memory_long_double; /* On Irix 6.5, gcc 3.4.3 can't compute compile-time NaN, and needs the runtime type conversion. */ #ifdef __sgi static long double NaNl () { double zero = 0.0; return zero / zero; } #else # define NaNl() (0.0L / 0.0L) #endif int main () { int result = 0; if (isinf (LDBL_MAX)) result |= 1; { memory_long_double m; unsigned int i; /* The isinf macro should be immune against changes in the sign bit and in the mantissa bits. The xor operation twiddles a bit that can only be a sign bit or a mantissa bit (since the exponent never extends to bit 31). */ m.value = NaNl (); m.word[NWORDS / 2] ^= (unsigned int) 1 << (sizeof (unsigned int) * CHAR_BIT - 1); for (i = 0; i < NWORDS; i++) m.word[i] |= 1; if (isinf (m.value)) result |= 2; } #if ((defined __ia64 && LDBL_MANT_DIG == 64) || (defined __x86_64__ || defined __amd64__) || (defined __i386 || defined __i386__ || defined _I386 || defined _M_IX86 || defined _X86_)) && !HAVE_SAME_LONG_DOUBLE_AS_DOUBLE /* Representation of an 80-bit 'long double' as an initializer for a sequence of 'unsigned int' words. */ # ifdef WORDS_BIGENDIAN # define LDBL80_WORDS(exponent,manthi,mantlo) \ { ((unsigned int) (exponent) << 16) | ((unsigned int) (manthi) >> 16), \ ((unsigned int) (manthi) << 16) | ((unsigned int) (mantlo) >> 16), \ (unsigned int) (mantlo) << 16 \ } # else # define LDBL80_WORDS(exponent,manthi,mantlo) \ { mantlo, manthi, exponent } # endif { /* Quiet NaN. */ static memory_long_double x = { LDBL80_WORDS (0xFFFF, 0xC3333333, 0x00000000) }; if (isinf (x.value)) result |= 2; } { /* Signalling NaN. */ static memory_long_double x = { LDBL80_WORDS (0xFFFF, 0x83333333, 0x00000000) }; if (isinf (x.value)) result |= 2; } /* isinf should return something even for noncanonical values. */ { /* Pseudo-NaN. */ static memory_long_double x = { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) }; if (isinf (x.value) && !isinf (x.value)) result |= 4; } { /* Pseudo-Infinity. */ static memory_long_double x = { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) }; if (isinf (x.value) && !isinf (x.value)) result |= 8; } { /* Pseudo-Zero. */ static memory_long_double x = { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) }; if (isinf (x.value) && !isinf (x.value)) result |= 16; } { /* Unnormalized number. */ static memory_long_double x = { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) }; if (isinf (x.value) && !isinf (x.value)) result |= 32; } { /* Pseudo-Denormal. */ static memory_long_double x = { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) }; if (isinf (x.value) && !isinf (x.value)) result |= 64; } #endif return result; }]])], [gl_cv_func_isinfl_works=yes], [gl_cv_func_isinfl_works=no], [case "$host_os" in mingw*) # Guess yes on mingw, no on MSVC. AC_EGREP_CPP([Known], [ #ifdef __MINGW32__ Known #endif ], [gl_cv_func_isinfl_works="guessing yes"], [gl_cv_func_isinfl_works="guessing no"]) ;; *) gl_cv_func_isinfl_works="guessing yes" ;; esac ]) ]) ])