Re: [PATCH] renameat: port to Solaris 10, which declares renameat in unistd.h

[Bruno Haible]

Paul Eggert wrote:
> The problem happens only in the gnulib renameat implementation itself.

No, it happens also for C++ programs that happen to use the 'renameat'
module.

Reproduce with
  $ ./gnulib-tool --create-testdir --dir=/tmp/testdir --with-tests 
--with-all-tests renameat
then build that directory on Solaris 10:

g++ -Wl,-R,/opt/csw/gcc4/lib -DHAVE_CONFIG_H -I.   -DGNULIB_STRICT_CHECKING=1  
-I. -I.  -I.. -I./..  -I../gllib -I./../gllib -I/home/haible/prefix-x86/include 
-Wall   -MT test-stdio-c++.o -MD -MP -MF .deps/test-stdio-c++.Tpo -c -o 
test-stdio-c++.o test-stdio-c++.cc
In file included from test-stdio-c++.cc:22:
../gllib/stdio.h:1100: error: 'renameat' was not declared in this scope
../gllib/stdio.h:1100: error: invalid type in declaration before ';' token
test-stdio-c++.cc:32: warning: 'signature_check32' defined but not used
test-stdio-c++.cc:135: warning: 'signature_check135' defined but not used
test-stdio-c++.cc:139: warning: 'signature_check140' defined but not used
*** Error code 1

The _GL_CXXALIASWARN (renameat); macro expects that the declaration of
renameat has already been seen by the compiler. It does not work when the
declaration comes afterwards.

> Having <stdio.h> pull in <unistd.h> would pollute the name
> space of all of gnulib's client code.

Yes, but we can limit the damage to Solaris systems and to packages that use
the 'renameat' module. Like we do in lib/string.in.h for example.

Here's a proposed patch. I verified that it fixes the compilation error
mentioned above. It also mentions the Solaris problem in the documentation
(like we do for all portability problems, regardless whether we add a
workaround to gnulib).


2010-10-26  Bruno Haible  <address@hidden>

        stdio: Work around compilation error due to renameat() on Solaris 10.
        * lib/stdio.in.h: Include <unistd.h> on Solaris.
        * lib/renameat.c: Don't include <unistd.h> here.
        * doc/posix-functions/renameat.texi: Mention the Solaris problem.
        Reported by Paul Eggert and Eric Blake.

--- lib/stdio.in.h.orig Wed Oct 27 01:10:15 2010
+++ lib/stdio.in.h      Wed Oct 27 01:01:59 2010
@@ -57,6 +57,13 @@
 # endif
 #endif
 
+/* Solaris 10 declares renameat in <unistd.h>, not in <stdio.h>.  */
+/* But in any case avoid namespace pollution on glibc systems.  */
+#if (@GNULIB_RENAMEAT@ || defined GNULIB_POSIXCHECK) && defined __sun \
+    && ! defined __GLIBC__
+# include <unistd.h>
+#endif
+
 
 /* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
 
--- lib/renameat.c.orig Wed Oct 27 01:10:15 2010
+++ lib/renameat.c      Wed Oct 27 01:00:24 2010
@@ -18,12 +18,6 @@
 
 #include <config.h>
 
-/* Solaris 10, which predates POSIX-2008, declares its renameat in
-   unistd.h.  Include unistd.h before including stdio.h, so that
-   gnulib's stdio.h doesn't #define renameat to rpl_renameat before
-   Solaris 10's unistd.h declares the system renameat.  */
-#include <unistd.h>
-
 #include <stdio.h>
 
 #if HAVE_RENAMEAT
--- doc/posix-functions/renameat.texi.orig      Wed Oct 27 01:10:15 2010
+++ doc/posix-functions/renameat.texi   Wed Oct 27 01:10:14 2010
@@ -17,6 +17,10 @@
 such that @code{renameat(fd,"link/",fd,"new")} corrupts @file{link}:
 Solaris 9.
 @item
+This function is declared in @code{<unistd.h>} instead of @code{<stdio.h>}
+on some platforms:
+Solaris 10.
address@hidden
 This function is missing on some platforms:
 glibc 2.3.6, MacOS X 10.3, FreeBSD 6.0, NetBSD 3.0, OpenBSD 3.8, AIX
 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 8, Cygwin 1.5.x, mingw,