| # log.m4 serial 11 |
| dnl Copyright (C) 2011-2020 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_LOG], |
| [ |
| m4_divert_text([DEFAULTS], [gl_log_required=plain]) |
| AC_REQUIRE([gl_MATH_H_DEFAULTS]) |
| |
| dnl Determine LOG_LIBM. |
| gl_COMMON_DOUBLE_MATHFUNC([log]) |
| |
| save_LIBS="$LIBS" |
| LIBS="$LIBS $LOG_LIBM" |
| gl_FUNC_LOG_WORKS |
| LIBS="$save_LIBS" |
| case "$gl_cv_func_log_works" in |
| *yes) ;; |
| *) REPLACE_LOG=1 ;; |
| esac |
| |
| m4_ifdef([gl_FUNC_LOG_IEEE], [ |
| if test $gl_log_required = ieee && test $REPLACE_LOG = 0; then |
| AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles |
| AC_CACHE_CHECK([whether log works according to ISO C 99 with IEC 60559], |
| [gl_cv_func_log_ieee], |
| [ |
| save_LIBS="$LIBS" |
| LIBS="$LIBS $LOG_LIBM" |
| AC_RUN_IFELSE( |
| [AC_LANG_SOURCE([[ |
| #ifndef __NO_MATH_INLINES |
| # define __NO_MATH_INLINES 1 /* for glibc */ |
| #endif |
| #include <math.h> |
| /* Compare two numbers with ==. |
| This is a separate function because IRIX 6.5 "cc -O" miscompiles an |
| 'x == x' test. */ |
| static int |
| numeric_equal (double x, double y) |
| { |
| return x == y; |
| } |
| static double dummy (double x) { return 0; } |
| int main (int argc, char *argv[]) |
| { |
| double (* volatile my_log) (double) = argc ? log : dummy; |
| /* Test log(negative). |
| This test fails on NetBSD 5.1, Solaris 11.4. */ |
| double y = my_log (-1.0); |
| if (numeric_equal (y, y)) |
| return 1; |
| return 0; |
| } |
| ]])], |
| [gl_cv_func_log_ieee=yes], |
| [gl_cv_func_log_ieee=no], |
| [case "$host_os" in |
| # Guess yes on glibc systems. |
| *-gnu* | gnu*) gl_cv_func_log_ieee="guessing yes" ;; |
| # Guess yes on musl systems. |
| *-musl*) gl_cv_func_log_ieee="guessing yes" ;; |
| # Guess yes on native Windows. |
| mingw*) gl_cv_func_log_ieee="guessing yes" ;; |
| # If we don't know, obey --enable-cross-guesses. |
| *) gl_cv_func_log_ieee="$gl_cross_guess_normal" ;; |
| esac |
| ]) |
| LIBS="$save_LIBS" |
| ]) |
| case "$gl_cv_func_log_ieee" in |
| *yes) ;; |
| *) REPLACE_LOG=1 ;; |
| esac |
| fi |
| ]) |
| ]) |
| |
| dnl Test whether log() works. |
| dnl On OSF/1 5.1, log(-0.0) is NaN. |
| AC_DEFUN([gl_FUNC_LOG_WORKS], |
| [ |
| AC_REQUIRE([AC_PROG_CC]) |
| AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles |
| AC_CACHE_CHECK([whether log works], [gl_cv_func_log_works], |
| [ |
| AC_RUN_IFELSE( |
| [AC_LANG_SOURCE([[ |
| #include <math.h> |
| volatile double x; |
| double y; |
| int main () |
| { |
| x = -0.0; |
| y = log (x); |
| if (!(y + y == y)) |
| return 1; |
| return 0; |
| } |
| ]])], |
| [gl_cv_func_log_works=yes], |
| [gl_cv_func_log_works=no], |
| [case "$host_os" in |
| osf*) gl_cv_func_log_works="guessing no" ;; |
| # Guess yes on native Windows. |
| mingw*) gl_cv_func_log_works="guessing yes" ;; |
| *) gl_cv_func_log_works="guessing yes" ;; |
| esac |
| ]) |
| ]) |
| ]) |