Cross-compiling lib/strtod.c failed on Mingw, as reported at
http://savannah.gnu.org/bugs/?29965:
strtod.c:37: error: redefinition of 'strtod'
/usr/i686-pc-mingw32/sys-root/mingw/include/stdlib.h:319: note:
previous definition of 'strtod' was here
The problem was the section of stdlib.h cited in the above
message:
double __cdecl __MINGW_NOTHROW __strtod (const char*, char**);
#ifdef __cplusplus
/* We require a function with external linkage. */
#else
static
#endif /* Not __cplusplus */
__inline__ double __cdecl __MINGW_NOTHROW
strtod (const char* __restrict__ __nptr, char** __restrict__ __endptr)
{
return __strtod(__nptr, __endptr);
}
float __cdecl __MINGW_NOTHROW strtof (const char * __restrict__, char **
__restrict__);
long double __cdecl __MINGW_NOTHROW strtold (const char * __restrict__,
char ** __restrict__);
As you can see, this defines an inline version of strtod() that
conflicts with the out-of-line version in lib/strtod.c.
Is there an idiomatic solution for this kind of problem? It is
the first time that I have run into this particular form of
brokenness before.
I'm appending my fix, which I have not yet pushed out.
--8<--------------------------cut here-------------------------->8--
>From 525a69cbe8d636ac1442aab4c6adb8df09b4b534 Mon Sep 17 00:00:00 2001
From: Ben Pfaff <b...@cs.stanford.edu>
Date: Thu, 10 Jun 2010 21:10:51 -0700
Subject: [PATCH] Bypass broken inline strtod() definition in <stdlib.h> on
Mingw.
* m4/strtod.m4: Detect broken inline strtod().
* lib/stdlib.in.h: Bypass broken inline strtod().
---
lib/stdlib.in.h | 11 +++++++++++
m4/strtod.m4 | 37 +++++++++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+), 0 deletions(-)
diff --git a/lib/stdlib.in.h b/lib/stdlib.in.h
index d74c251..e982fea 100644
--- a/lib/stdlib.in.h
+++ b/lib/stdlib.in.h
@@ -29,9 +29,20 @@
#ifndef _GL_STDLIB_H
+#ifdef HAVE_BROKEN_INLINE_STRTOD_DEFINITION
+/* strtod() is broken and must be replaced, but <stdlib.h> defines a inline
+ strtod() that ordinarily prevents it from being replaced, so we must use a
+ macro to rename it temporarily. */
+#define strtod _gl_broken_inline_strtod
+#endif
+
/* The include_next requires a split double-inclusion guard. */
#...@include_next@ @NEXT_STDLIB_H@
+#ifdef HAVE_BROKEN_INLINE_STRTOD_DEFINITION
+#undef strtod
+#endif
+
#ifndef _GL_STDLIB_H
#define _GL_STDLIB_H
diff --git a/m4/strtod.m4 b/m4/strtod.m4
index 4cccb6d..47597be 100644
--- a/m4/strtod.m4
+++ b/m4/strtod.m4
@@ -82,6 +82,43 @@ numeric_equal (double x, double y)
_AC_LIBOBJ_STRTOD
fi
fi
+
+ if test "$gl_cv_func_strtod_works" != yes; then
+ dnl Mingw defines an inline version of strtod() in <stdlib.h>,
+ dnl which prevents replacing it unless we #define strtod to
+ dnl something else before including <stdlib.h> and then #undef
+ dnl it afterward.
+ AC_CACHE_CHECK([whether strtod may safely be defined],
+ [gl_cv_func_strtod_may_define],
+ [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#include <stdlib.h>
+double strtod (const char *nptr, char **endptr)
+{
+}
+]])],
+ [gl_cv_func_strtod_may_define=yes],
+ [gl_cv_func_strtod_may_define=no])])
+ if test $gl_cv_func_strtod_may_define = no; then
+ AC_CACHE_CHECK([whether strtod may be moved aside and defined],
+ [gl_cv_func_strtod_move_aside],
+ [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#define strtod busted_strtod
+#include <stdlib.h>
+#undef strtod
+double strtod (const char *nptr, char **endptr)
+{
+}
+]])],
+ [gl_cv_func_strtod_move_aside=yes],
+ [gl_cv_func_strtod_move_aside=no])])
+ if test $gl_cv_func_strtod_move_aside = yes; then
+ AC_DEFINE([HAVE_BROKEN_INLINE_STRTOD_DEFINITION], [1],
+ [Define to 1 if a broken strtod() must be replaced, but
+ <stdlib.h> defines a inline strtod() that ordinarily
+ prevents it from being replaced.])
+ fi
+ fi
+ fi
])
# Prerequisites of lib/strtod.c.
--
1.7.1
--
Ben Pfaff
http://benpfaff.org
