Thread (13 messages) flat view 13 messages, 4 authors, 2016-06-15

Re: [RFC/PATCH 1/2] Teach Solaris that _XOPEN_SOURCE=600 really menas XPG6

From: Brandon Casey <hidden>
Date: 2016-06-15 22:46:52

Junio C Hamano wrote:
quoted hunk ↗ jump to hunk
In git-compat-util.h, we do

    #define _XOPEN_SOURCE 600
    #define _XOPEN_SOURCE_EXTENDED 1

unless we are on BSD or SCO.

On OpenSolaris (200811), /usr/include/sys/feature_tests.h has this nice
table:

    Feature Test Macro				     Specification
    ------------------------------------------------  -------------
    _XOPEN_SOURCE                                         XPG3
    _XOPEN_SOURCE && _XOPEN_VERSION = 4                   XPG4
    _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED = 1           XPG4v2
    _XOPEN_SOURCE = 500                                   XPG5
    _XOPEN_SOURCE = 600  (or POSIX_C_SOURCE=200112L)      XPG6

Later in the same header, compilation with -c99 is made to fail if _XPG6 is
not set, like this:

    #if defined(_STDC_C99) && (defined(__XOPEN_OR_POSIX) && !defined(_XPG6))
    #error "Compiler or options invalid for pre-UNIX 03 X/Open applications \
            and pre-2001 POSIX applications"
    #elif ...

The problem is that they check things in an order that is inconvenient for
us.  When they see _XOPEN_SOURCE_EXTENDED, they declare that we are XPG4v2,
regardless of the value of _XOPEN_SOURCE.

To work around this problem, do not define _XOPEN_SOURCE_EXTENDED on
Sun's.

Signed-off-by: Junio C Hamano <redacted>
---
 git-compat-util.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/git-compat-util.h b/git-compat-util.h
index c7cf2d5..4236647 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -41,8 +41,10 @@
 
 #if !defined(__APPLE__) && !defined(__FreeBSD__)  && !defined(__USLC__) && !defined(_M_UNIX)
 #define _XOPEN_SOURCE 600 /* glibc2 and AIX 5.3L need 500, OpenBSD needs 600 for S_ISLNK() */
+#ifndef __sun__
__sun__ is not defined by the SUNWspro compiler.  We can fix that by adding
a -D__sun__ in the SunOS section of the Makefile though.

A more important issue, is that now that this causes _XPG6 to be defined,
sun's header files _require_ a c99 compiler to be used.

Here's the comment that goes along with the partial snippet that you showed
above from /usr/include/sys/feature_tests.h:

  /*
   * It is invalid to compile an XPG3, XPG4, XPG4v2, or XPG5 application
   * using c99.  The same is true for POSIX.1-1990, POSIX.2-1992, POSIX.1b,
   * and POSIX.1c applications. Likewise, it is invalid to compile an XPG6
   * or a POSIX.1-2001 application with anything other than a c99 or later
   * compiler.  Therefore, we force an error in both cases.
   */

And the rest of the macro implements the check for source/compiler
suitability.

So we either require compiling with a c99 compiler (by ensuring that
_XPG6 is set) or exclude compiling with a c99 compiler on sun (by
ensuring that _XPG6 is not set).  Actually, this would only affect Solaris
versions which support XPG6.  Solaris 11 and 10 do.  I don't know about
Solaris 9 and 8.  Solaris 7 doesn't.

Which do we want to do?
 #define _XOPEN_SOURCE_EXTENDED 1 /* AIX 5.3L needs this */
 #endif
+#endif
 #define _ALL_SOURCE 1
 #define _GNU_SOURCE 1
 #define _BSD_SOURCE 1
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