Re: cygwin bugs in unistd

[Bruno Haible]

Eric Blake wrote:
> --- a/lib/unistd.in.h
> +++ b/lib/unistd.in.h
> @@ -33,10 +33,17 @@
>  #include <stddef.h>
> 
>  /* mingw doesn't define the SEEK_* or *_FILENO macros in <unistd.h>.  */
> -#if !(defined SEEK_CUR && defined SEEK_END && defined SEEK_SET)
> +/* Cygwin 1.7.1 declares symlinkat in <stdio.h>, not in <unistd.h>.  */
> +#if (!(defined SEEK_CUR && defined SEEK_END && defined SEEK_SET) \
> +     || @GNULIB_SYMLINKAT@)
>  # include <stdio.h>
>  #endif
> 
> +/* Cygwin 1.7.1 declares unlinkat in <fcntl.h>, not in <unistd.h>.  */
> +#if @GNULIB_UNLINKAT@
> +# include <fcntl.h>
> +#endif

Hmm, I'm not so happy to see additional headers being included, even on
glibc systems. This "namespace pollution" has the effect that a developer
will, for example, write code that does

  #include <unistd.h>
  ... { printf (...); }

and get no error because <unistd.h> happens to drag in <stdio.h>. It's
not possible to avoid all possible #include on all platforms - gnulib
provides them precisely because they are necessary on some platforms -,
but for glibc systems, where most developers write and test their programs,
I can make an extra effort to exclude unnecessary headers.

In fact, one example of such a mistake is already present in lib/fcntl.c.

Applying this:


2009-12-24  Bruno Haible  <address@hidden>

        Reduce namespace pollution on glibc systems.
        * lib/inttypes.in.h: Don't include <stdint.h> on glibc systems.
        * lib/stdlib.in.h: Don't include <stdint.h>, <unistd.h> on glibc
        systems.
        * lib/unistd.in.h: Don't include <stdio.h>, <fcntl.h>, <stdlib.h>,
        <getopt.h> on glibc systems.
        * lib/fcntl.in.h: Don't include <sys/stat.h>, <unistd.h> on glibc
        systems.
        * lib/fcntl.c: Include <unistd.h> here instead.

--- lib/inttypes.in.h.orig      Thu Dec 24 16:57:08 2009
+++ lib/inttypes.in.h   Thu Dec 24 16:54:49 2009
@@ -36,8 +36,11 @@
 #if ! defined INTTYPES_H && ! defined _GL_JUST_INCLUDE_SYSTEM_INTTYPES_H
 #define INTTYPES_H
 
-/* Include <stdint.h> or the gnulib replacement.  */
-#include <stdint.h>
+/* Include <stdint.h> or the gnulib replacement.
+   But avoid namespace pollution on glibc systems.  */
+#ifndef __GLIBC__
+# include <stdint.h>
+#endif
 /* Get CHAR_BIT.  */
 #include <limits.h>
 
--- lib/stdlib.in.h.orig        Thu Dec 24 16:57:09 2009
+++ lib/stdlib.in.h     Thu Dec 24 16:55:51 2009
@@ -49,8 +49,8 @@
 # include <random.h>
 #endif
 
-#if (@GNULIB_RANDOM_R@ || address@hidden@ \
-     || defined GNULIB_POSIXCHECK)
+#if address@hidden@ || (@GNULIB_RANDOM_R@ && address@hidden@) \
+    || defined GNULIB_POSIXCHECK
 # include <stdint.h>
 #endif
 
@@ -67,9 +67,10 @@
 };
 #endif
 
-#if @GNULIB_MKSTEMP@ || @GNULIB_GETSUBOPT@ || defined GNULIB_POSIXCHECK
+#if (@GNULIB_MKSTEMP@ || @GNULIB_GETSUBOPT@ || defined GNULIB_POSIXCHECK) && ! 
defined __GLIBC__
 /* On MacOS X 10.3, only <unistd.h> declares mkstemp.  */
 /* On Cygwin 1.7.1, only <unistd.h> declares getsubopt.  */
+/* But avoid namespace pollution on glibc systems.  */
 # include <unistd.h>
 #endif
 
--- lib/unistd.in.h.orig        Thu Dec 24 16:57:09 2009
+++ lib/unistd.in.h     Thu Dec 24 16:56:52 2009
@@ -34,20 +34,26 @@
 
 /* mingw doesn't define the SEEK_* or *_FILENO macros in <unistd.h>.  */
 /* Cygwin 1.7.1 declares symlinkat in <stdio.h>, not in <unistd.h>.  */
+/* But avoid namespace pollution on glibc systems.  */
 #if (!(defined SEEK_CUR && defined SEEK_END && defined SEEK_SET) \
-     || @GNULIB_SYMLINKAT@ || defined GNULIB_POSIXCHECK)
+     || (@GNULIB_SYMLINKAT@ || defined GNULIB_POSIXCHECK)) \
+    && ! defined __GLIBC__
 # include <stdio.h>
 #endif
 
 /* Cygwin 1.7.1 declares unlinkat in <fcntl.h>, not in <unistd.h>.  */
-#if @GNULIB_UNLINKAT@ || defined GNULIB_POSIXCHECK
+/* But avoid namespace pollution on glibc systems.  */
+#if (@GNULIB_UNLINKAT@ || defined GNULIB_POSIXCHECK) && ! defined __GLIBC__
 # include <fcntl.h>
 #endif
 
 /* mingw fails to declare _exit in <unistd.h>.  */
 /* mingw, BeOS, Haiku declare environ in <stdlib.h>, not in <unistd.h>.  */
 /* Solaris declares getcwd not only in <unistd.h> but also in <stdlib.h>.  */
-#include <stdlib.h>
+/* But avoid namespace pollution on glibc systems.  */
+#ifndef __GLIBC__
+# include <stdlib.h>
+#endif
 
 /* mingw declares getcwd in <io.h>, not in <unistd.h>.  */
 #if ((@GNULIB_GETCWD@ || defined GNULIB_POSIXCHECK) \
@@ -63,8 +69,9 @@
 # include <sys/types.h>
 #endif
 
-/* Get getopt(), optarg, optind, opterr, optopt.  */
-#if @GNULIB_UNISTD_H_GETOPT@ && !defined _GL_SYSTEM_GETOPT
+/* Get getopt(), optarg, optind, opterr, optopt.
+   But avoid namespace pollution on glibc systems.  */
+#if @GNULIB_UNISTD_H_GETOPT@ && !defined __GLIBC__ && !defined 
_GL_SYSTEM_GETOPT
 # include <getopt.h>
 #endif
 
--- lib/fcntl.in.h.orig Thu Dec 24 16:57:08 2009
+++ lib/fcntl.in.h      Thu Dec 24 16:54:17 2009
@@ -25,8 +25,10 @@
 /* Special invocation convention.  */
 
 #include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
+#ifndef __GLIBC__ /* Avoid namespace pollution on glibc systems.  */
+# include <sys/stat.h>
+# include <unistd.h>
+#endif
 address@hidden@ @NEXT_FCNTL_H@
 
 #else
@@ -35,8 +37,10 @@
 #ifndef _GL_FCNTL_H
 
 #include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
+#ifndef __GLIBC__ /* Avoid namespace pollution on glibc systems.  */
+# include <sys/stat.h>
+# include <unistd.h>
+#endif
 /* The include_next requires a split double-inclusion guard.  */
 address@hidden@ @NEXT_FCNTL_H@
 
--- lib/fcntl.c.orig    Thu Dec 24 16:57:08 2009
+++ lib/fcntl.c Thu Dec 24 16:43:30 2009
@@ -25,6 +25,7 @@
 #include <errno.h>
 #include <limits.h>
 #include <stdarg.h>
+#include <unistd.h>
 
 #if !HAVE_FCNTL
 # define rpl_fcntl fcntl