getcwd: on Solaris, work better if ancestors are inaccessible

[gnulib.git] / m4 / strtod.m4

diff --git a/m4/strtod.m4 b/m4/strtod.m4
index 4cccb6d..8f90ed7 100644 (file)
--- a/m4/strtod.m4
+++ b/m4/strtod.m4
@@ -1,4 +1,4 @@
-# strtod.m4 serial 14
+# strtod.m4 serial 16
 dnl Copyright (C) 2002-2003, 2006-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,11 +7,14 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_STRTOD],
 [
   AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
-  AC_FUNC_STRTOD
-  dnl Note: AC_FUNC_STRTOD does AC_LIBOBJ([strtod]).
-  if test $ac_cv_func_strtod = no; then
+  dnl Test whether strtod is declared.
+  dnl Don't call AC_FUNC_STRTOD, because it does not have the right guess
+  dnl when cross-compiling.
+  dnl Don't call AC_CHECK_FUNCS([strtod]) because it would collide with the
+  dnl ac_cv_func_strtod variable set by the AC_FUNC_STRTOD macro.
+  AC_CHECK_DECLS_ONCE([strtod])
+  if test $ac_cv_have_decl_strtod != yes; then
     HAVE_STRTOD=0
-    gl_PREREQ_STRTOD
   else
     AC_CACHE_CHECK([whether strtod obeys C99], [gl_cv_func_strtod_works],
       [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
@@ -28,6 +31,24 @@ numeric_equal (double x, double y)
 }
 ]], [[
   {
+    /* In some old versions of Linux (2000 or before), strtod mis-parses
+       strings with leading '+'.  */
+    const char *string = " +69";
+    char *term;
+    double value = strtod (string, &term);
+    if (value != 69 || term != (string + 4))
+      return 1;
+  }
+  {
+    /* Under Solaris 2.4, strtod returns the wrong value for the
+       terminating character under some conditions.  */
+    const char *string = "NaN";
+    char *term;
+    strtod (string, &term);
+    if (term != string && *(term - 1) == 0)
+      return 1;
+  }
+  {
     /* Older glibc and Cygwin mis-parse "-0x".  */
     const char *string = "-0x";
     char *term;
@@ -74,16 +95,34 @@ numeric_equal (double x, double y)
 ]])],
         [gl_cv_func_strtod_works=yes],
         [gl_cv_func_strtod_works=no],
-        [gl_cv_func_strtod_works="guessing no"])])
+        [dnl The last known bugs in glibc strtod(), as of this writing,
+        dnl were fixed in version 2.8
+         AC_EGREP_CPP([Lucky user],
+           [
+#include <features.h>
+#ifdef __GNU_LIBRARY__
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 8) || (__GLIBC__ > 2)
+  Lucky user
+ #endif
+#endif
+           ],
+           [gl_cv_func_strtod_works=yes],
+           [gl_cv_func_strtod_works="guessing no"])])])
     if test "$gl_cv_func_strtod_works" != yes; then
       REPLACE_STRTOD=1
-      gl_PREREQ_STRTOD
-      dnl Use undocumented macro to set POW_LIB correctly.
-      _AC_LIBOBJ_STRTOD
     fi
   fi
+  if test $HAVE_STRTOD = 0 || test $REPLACE_STRTOD = 1; then
+    AC_LIBOBJ([strtod])
+    gl_PREREQ_STRTOD
+  fi
 ])
 
 # Prerequisites of lib/strtod.c.
-# The need for pow() is already handled by AC_FUNC_STRTOD.
-AC_DEFUN([gl_PREREQ_STRTOD], [:])
+AC_DEFUN([gl_PREREQ_STRTOD], [
+  AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM])
+  if test $gl_cv_func_ldexp_no_libm = yes; then
+    AC_DEFINE([HAVE_LDEXP_IN_LIBC], [1],
+      [Define if the ldexp function is available in libc.])
+  fi
+])