From: Bruno Haible <bruno@clisp.org>
Date: Tue, 9 Sep 2025 10:42:31 +0000 (+0200)
Subject: log: Remove support for OSF/1.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1dda904ee97ec8dff91ed0c29ab6f39ff494695;p=thirdparty%2Fgnulib.git

log: Remove support for OSF/1.

* m4/log.m4 (gl_FUNC_LOG_WORKS): Remove macro.
(gl_FUNC_LOG): Don't invoke it.
* lib/log.c (log): Assume that log (±0.0) is correct.
---

diff --git a/ChangeLog b/ChangeLog
index a03ca39e42..84e0e1c398 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2025-09-09  Bruno Haible  <bruno@clisp.org>
 
+	log: Remove support for OSF/1.
+	* m4/log.m4 (gl_FUNC_LOG_WORKS): Remove macro.
+	(gl_FUNC_LOG): Don't invoke it.
+	* lib/log.c (log): Assume that log (±0.0) is correct.
+
 	localcharset: Remove support for OSF/1.
 	* lib/localcharset.h: Update comments.
 	* lib/localcharset.c (alias_table): Remove entries for OSF/1.
diff --git a/lib/log.c b/lib/log.c
index 039870cd93..5c3be856b9 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -23,16 +23,11 @@ double
 log (double x)
 #undef log
 {
-  if (x <= 0.0)
+  if (x < 0.0)
     {
-      /* Work around the OSF/1 5.1 bug.  */
-      if (x == 0.0)
-        /* Return -Infinity.  */
-        return -1.0 / 0.0;
       /* Work around the NetBSD 5.1, Solaris 11.0 bug.  */
-      else /* x < 0.0 */
-        /* Return NaN.  */
-        return 0.0 / 0.0;
+      /* Return NaN.  */
+      return 0.0 / 0.0;
     }
   return log (x);
 }
diff --git a/m4/log.m4 b/m4/log.m4
index d362713ec5..aedfb24ebf 100644
--- a/m4/log.m4
+++ b/m4/log.m4
@@ -1,5 +1,5 @@
 # log.m4
-# serial 14
+# serial 15
 dnl Copyright (C) 2011-2025 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -14,17 +14,8 @@ AC_DEFUN([gl_FUNC_LOG],
   dnl Determine LOG_LIBM.
   gl_COMMON_DOUBLE_MATHFUNC([log])
 
-  saved_LIBS="$LIBS"
-  LIBS="$LIBS $LOG_LIBM"
-  gl_FUNC_LOG_WORKS
-  LIBS="$saved_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
+    if test $gl_log_required = ieee; then
       AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
       AC_CACHE_CHECK([whether log works according to ISO C 99 with IEC 60559],
         [gl_cv_func_log_ieee],
@@ -79,37 +70,3 @@ int main (int argc, char *argv[])
     fi
   ])
 ])
-
-dnl Test whether log() works.
-dnl On OSF/1 5.1, log(-0.0) is NaN.
-AC_DEFUN([gl_FUNC_LOG_WORKS],
-[
-  AC_REQUIRE([AC_PROG_CC])
-  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
-  AC_CACHE_CHECK([whether log works], [gl_cv_func_log_works],
-    [
-      AC_RUN_IFELSE(
-        [AC_LANG_SOURCE([[
-#include <math.h>
-volatile double x;
-double y;
-int main ()
-{
-  x = -0.0;
-  y = log (x);
-  if (!(y + y == y))
-    return 1;
-  return 0;
-}
-]])],
-        [gl_cv_func_log_works=yes],
-        [gl_cv_func_log_works=no],
-        [case "$host_os" in
-           osf*)              gl_cv_func_log_works="guessing no" ;;
-                              # Guess yes on native Windows.
-           mingw* | windows*) gl_cv_func_log_works="guessing yes" ;;
-           *)                 gl_cv_func_log_works="guessing yes" ;;
-         esac
-        ])
-    ])
-])