On Tue, Jan 15, 2008 at 12:28:55AM +0100, Bruno Haible wrote:
> You fixed the first portability problem: the function is missing on some
> platforms. But there is another one.
>
> I want to use the replacement in GNU clisp, so I did "man strsignal", and it
> says:
>
> "On some systems (but not on Linux), a NULL pointer may be returned
> instead for an invalid signal number."
>
> And it's even worse than that: for negative or out-of-range signal numbers,
>
> * Solaris strsignal returns NULL,
> * AIX 5.1 strsignal returns (char*)(-1) !
>
> As a user of this function, I don't want to special case these return values.
> The function should always return a reasonable pointer.
Thanks for pointing this out.
> So I propose to change the module so that, on these two platforms, it
> overrides the system function. Do you agree? May I do this? Do you want to
> do it?
I think the attached patch is right (I tested it with LIBS=-lstrsignal
after installing a bogus /usr/lib/libstrsignal.a with a strsignal
function that always returns NULL), but would appreciate review from
those more fluent in Autoconf than I am.
Is it sufficient to test a single value? It's been some time since I had
convenient access to either Solaris or AIX systems.
Cheers,
--
Colin Watson [EMAIL PROTECTED]
diff --git a/lib/string.in.h b/lib/string.in.h
index 3354d20..7e6bd08 100644
--- a/lib/string.in.h
+++ b/lib/string.in.h
@@ -542,7 +542,10 @@ extern char *strerror (int);
#endif
#if @GNULIB_STRSIGNAL@
-# if ! @HAVE_DECL_STRSIGNAL@
+# if @REPLACE_STRSIGNAL@
+# define strsignal rpl_strsignal
+# endif
+# if ! @HAVE_DECL_STRSIGNAL@ || @REPLACE_STRSIGNAL@
extern char *strsignal (int __sig);
# endif
#elif defined GNULIB_POSIXCHECK
diff --git a/m4/string_h.m4 b/m4/string_h.m4
index 69761d7..12fa1bf 100644
--- a/m4/string_h.m4
+++ b/m4/string_h.m4
@@ -80,6 +80,7 @@ AC_DEFUN([gl_HEADER_STRING_H_DEFAULTS],
HAVE_DECL_STRERROR=1; AC_SUBST([HAVE_DECL_STRERROR])
HAVE_DECL_STRSIGNAL=1; AC_SUBST([HAVE_DECL_STRSIGNAL])
REPLACE_STRERROR=0; AC_SUBST([REPLACE_STRERROR])
+ REPLACE_STRSIGNAL=0; AC_SUBST([REPLACE_STRSIGNAL])
REPLACE_MEMMEM=0; AC_SUBST([REPLACE_MEMMEM])
REPLACE_STRSTR=0; AC_SUBST([REPLACE_STRSTR])
])
diff --git a/m4/strsignal.m4 b/m4/strsignal.m4
index 9bcd374..e6f275b 100644
--- a/m4/strsignal.m4
+++ b/m4/strsignal.m4
@@ -12,10 +12,34 @@ AC_DEFUN([gl_FUNC_STRSIGNAL],
AC_REQUIRE([AC_DECL_SYS_SIGLIST])
AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
- AC_REPLACE_FUNCS([strsignal])
+
AC_CHECK_DECLS_ONCE([strsignal])
if test $ac_cv_have_decl_strsignal = no; then
HAVE_DECL_STRSIGNAL=0
+ fi
+
+ AC_CHECK_FUNCS([strsignal])
+ if test $ac_cv_func_strsignal = yes; then
+ dnl Check if strsignal behaves reasonably for out-of-range signal numbers.
+ dnl Solaris returns NULL; AIX 5.1 returns (char *) -1.
+ AC_CACHE_CHECK([for working strsignal function],
+ [gl_cv_func_working_strsignal],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <string.h>
+ ]],
+ [[char *s = strsignal (-1);
+ return !(s != (char *) 0 && s != (char *) -1);]])],
+ [gl_cv_func_working_strsignal=yes],
+ [gl_cv_func_working_strsignal=no],
+ [gl_cv_func_working_strsignal=cross-compiling])])
+ else
+ gl_cv_func_working_strsignal=no
+ fi
+
+ if test $gl_cv_func_working_strsignal != yes; then
+ REPLACE_STRSIGNAL=1
+ AC_LIBOBJ([strsignal])
gl_PREREQ_STRSIGNAL
fi
])
diff --git a/modules/string b/modules/string
index 0a2fd71..f59a11e 100644
--- a/modules/string
+++ b/modules/string
@@ -72,6 +72,7 @@ string.h: string.in.h
-e 's|@''REPLACE_MEMMEM''@|$(REPLACE_MEMMEM)|g' \
-e 's|@''REPLACE_STRSTR''@|$(REPLACE_STRSTR)|g' \
-e 's|@''REPLACE_STRERROR''@|$(REPLACE_STRERROR)|g' \
+ -e 's|@''REPLACE_STRSIGNAL''@|$(REPLACE_STRSIGNAL)|g' \
-e '/definition of GL_LINK_WARNING/r $(LINK_WARNING_H)' \
< $(srcdir)/string.in.h; \
} > [EMAIL PROTECTED]
diff --git a/tests/test-strsignal.c b/tests/test-strsignal.c
index 16544f2..fa4c70f 100644
--- a/tests/test-strsignal.c
+++ b/tests/test-strsignal.c
@@ -65,5 +65,9 @@ main (int argc, char **argv)
ASSERT_DESCRIPTION (str, "Interrupt");
#endif
+ str = strsignal (-1);
+ ASSERT (str);
+ ASSERT (str != (char *) -1);
+
return 0;
}
