diff options
Diffstat (limited to 'm4/trunc.m4')
-rw-r--r-- | m4/trunc.m4 | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/m4/trunc.m4 b/m4/trunc.m4 new file mode 100644 index 000000000..154afc67d --- /dev/null +++ b/m4/trunc.m4 @@ -0,0 +1,101 @@ +# trunc.m4 serial 15 +dnl Copyright (C) 2007, 2010-2023 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_FUNC_TRUNC], +[ + m4_divert_text([DEFAULTS], [gl_trunc_required=plain]) + AC_REQUIRE([gl_MATH_H_DEFAULTS]) + dnl Persuade glibc <math.h> to declare trunc(). + AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) + dnl Test whether trunc() is declared. + AC_CHECK_DECLS([trunc], , , [[#include <math.h>]]) + if test "$ac_cv_have_decl_trunc" = yes; then + dnl Test whether trunc() can be used without libm. + TRUNC_LIBM=? + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#ifndef __NO_MATH_INLINES + # define __NO_MATH_INLINES 1 /* for glibc */ + #endif + #include <math.h> + double (*funcptr) (double) = trunc; + double x;]], + [[x = funcptr(x) + trunc(x);]])], + [TRUNC_LIBM=]) + if test "$TRUNC_LIBM" = "?"; then + save_LIBS="$LIBS" + LIBS="$LIBS -lm" + AC_LINK_IFELSE( + [AC_LANG_PROGRAM( + [[#ifndef __NO_MATH_INLINES + # define __NO_MATH_INLINES 1 /* for glibc */ + #endif + #include <math.h> + double (*funcptr) (double) = trunc; + double x;]], + [[x = funcptr(x) + trunc(x);]])], + [TRUNC_LIBM="-lm"]) + LIBS="$save_LIBS" + fi + if test "$TRUNC_LIBM" = "?"; then + TRUNC_LIBM= + fi + m4_ifdef([gl_FUNC_TRUNC_IEEE], [ + if test $gl_trunc_required = ieee && test $REPLACE_TRUNC = 0; then + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_CACHE_CHECK([whether trunc works according to ISO C 99 with IEC 60559], + [gl_cv_func_trunc_ieee], + [ + save_LIBS="$LIBS" + LIBS="$LIBS $TRUNC_LIBM" + AC_RUN_IFELSE( + [AC_LANG_SOURCE([[ +#ifndef __NO_MATH_INLINES +# define __NO_MATH_INLINES 1 /* for glibc */ +#endif +#include <math.h> +]gl_DOUBLE_MINUS_ZERO_CODE[ +]gl_DOUBLE_SIGNBIT_CODE[ +static double dummy (double f) { return 0; } +int main (int argc, char *argv[]) +{ + double (* volatile my_trunc) (double) = argc ? trunc : dummy; + /* Test whether trunc (-0.0) is -0.0. */ + if (signbitd (minus_zerod) && !signbitd (my_trunc (minus_zerod))) + return 1; + return 0; +} + ]])], + [gl_cv_func_trunc_ieee=yes], + [gl_cv_func_trunc_ieee=no], + [case "$host_os" in + # Guess yes on glibc systems. + *-gnu* | gnu*) gl_cv_func_trunc_ieee="guessing yes" ;; + # Guess yes on musl systems. + *-musl*) gl_cv_func_trunc_ieee="guessing yes" ;; + # Guess yes on native Windows. + mingw*) gl_cv_func_trunc_ieee="guessing yes" ;; + # If we don't know, obey --enable-cross-guesses. + *) gl_cv_func_trunc_ieee="$gl_cross_guess_normal" ;; + esac + ]) + LIBS="$save_LIBS" + ]) + case "$gl_cv_func_trunc_ieee" in + *yes) ;; + *) REPLACE_TRUNC=1 ;; + esac + fi + ]) + else + HAVE_DECL_TRUNC=0 + fi + if test $HAVE_DECL_TRUNC = 0 || test $REPLACE_TRUNC = 1; then + dnl No libraries are needed to link lib/trunc.c. + TRUNC_LIBM= + fi + AC_SUBST([TRUNC_LIBM]) +]) |