Re: definition of waitpid in sys_wait.in.h for C++ on windows

[Bruno Haible]

Hi,

Tatsuro MATSUOKA wrote:
> Hello
> 
> I am tring to build octave-3.3.52+ on MinGW (GCC-4.5.0) which uses the
> gnulib.
> In compliling oct-env.cc  I have met the following error
> 
> libtool: compile:  g++ -shared-libgcc -DHAVE_CONFIG_H -I.
> -I../../../hg/octave-work/liboctave -I.. -I/c/Programs/gpnewlib/include
> -I/c/Programs/OctaveLibs/include -I/GnuWin32/include -I../libgnu
> -I../../../hg/octave-work/libgnu -I../../../hg/octave-work/libcruft/misc
> -I/c/Programs/gpnewlib/include -I/c/Programs/OctaveLibs/include
> -I/GnuWin32/include -O3 -fomit-frame-pointer -DHAVE_CONFIG_H -mieee-fp
> -IC:/Programs/GnuWin32/include -I/c/Programs/gpnewlib/include/freetype2
> -I/c/Programs/gpnewlib/include -IC:/Programs/gpnewlib/include -Wall -W
> -Wshadow -Wold-style-cast -Wformat -O3 -fomit-frame-pointer -O3
> -fomit-frame-pointer -MT liboctave_la-oct-env.lo -MD -MP -MF
> .deps/liboctave_la-oct-env.Tpo -c
> ../../../hg/octave-work/liboctave/oct-env.cc  -DDLL_EXPORT -DPIC -o
> .libs/liboctave_la-oct-env.o
> In file included from ../../../hg/octave-work/liboctave/oct-env.cc:61:0:
> ../../../hg/octave-work/liboctave/oct-syscalls.h:61:62: error: macro
> "waitpid" passed 4 arguments, but takes just 3
> ../../../hg/octave-work/liboctave/oct-syscalls.h:60:16: error: expected
> identifier before numeric constant
> ../../../hg/octave-work/liboctave/oct-syscalls.h:60:16: error: expected ','
> or '...' before numeric constant
> ../../../hg/octave-work/liboctave/oct-env.cc: In member function
> 'std::string octave_env::do_get_host_name() const':
> ../../../hg/octave-work/liboctave/oct-env.cc:455:20: error: 'gethostname'
> is not a member of 'gnulib'
> 
> 
> I have reported the above in the octave-maintainer ML,
> John suggested that for the first error
> ******************
> | In sys/wait.h in the directory 'libgnu' in the build tree, I found 
> | 
> | ... 
> | 
> | # define waitpid(pid,statusp,options) _cwait (statusp, pid, WAIT_CHILD) 
> 
> We need to discuss this with the gnulib maintainers.  For C++, it 
> would be helpful if this were a function instead of a macro. 
> ******************
> In file included from ../../../hg/octave-work/liboctave/oct-env.cc:61:0:
> ../../../hg/octave-work/liboctave/oct-syscalls.h:61:62: error: macro
> "waitpid" passed 4 arguments, but takes just 3
> 
> In oct-syscalls.h, there defined
> 
> 60:  static pid_t waitpid (pid_t, int *status, int);
> 61:  static pid_t waitpid (pid_t, int *status, int, std::string&);
> ***************
> 
> Perhaps John pointed for line 61 of oct-syscalls.h.
> *********
> For C++, it 
> would be helpful if this were a function instead of a macro. 
> ***********

Thanks for the report. Indeed, for C++ it's needed to make 'waitpid' a
function instead of a macro. Unfortunately an inline function in sys_wait.in.h
won't do it (it leads to an assembler error message on mingw). So I move
this function's definition to a separate file.


2010-09-29  Bruno Haible  <address@hidden>

        New module 'waitpid'.
        * lib/waitpid.c: New file, extracted from lib/sys_wait.in.h.
        * lib/sys_wait.in.h: Include <sys/types.h>, c++defs.h, warn-on-use.h.
        Don't include <process.h>.
        (waitpid): Declare only, using modern idiom.
        * m4/waitpid.m4: New file.
        * m4/sys_wait_h.m4 (gl_SYS_WAIT_H): Check whether waitpid is declared.
        * modules/waitpid: New file.
        * modules/sys_wait (Depends-on): Add c++defs, warn-on-use, waitpid.
        (Makefile.am): Update.
        Reported by Tatsuro MATSUOKA <address@hidden>.

================================ lib/waitpid.c ================================
/* Wait for process state change.
   Copyright (C) 2001-2003, 2005-2010 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */

#include <config.h>

/* Specification.  */
#include <sys/wait.h>

/* Implementation for native Win32 systems.  */

#include <process.h> /* for _cwait, WAIT_CHILD */

pid_t
waitpid (pid_t pid, int *statusp, int options)
{
  return _cwait (statusp, pid, WAIT_CHILD);
}
================================ m4/waitpid.m4 ================================
# waitpid.m4 serial 1
dnl Copyright (C) 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_WAITPID],
[
  AC_REQUIRE([AC_CANONICAL_HOST])
  case $host_os in
    mingw*)
      AC_LIBOBJ([waitpid])
      ;;
  esac
])
=============================== modules/waitpid ===============================
Description:
waitpid() function: wait for process state change

Files:
lib/waitpid.c
m4/waitpid.m4

Depends-on:
sys_wait

configure.ac:
gl_FUNC_WAITPID

Makefile.am:

Include:
<sys/wait.h>

License:
LGPLv2+

Maintainer:
Bruno Haible
===============================================================================
--- lib/sys_wait.in.h.orig      Wed Sep 29 13:15:34 2010
+++ lib/sys_wait.in.h   Wed Sep 29 13:10:32 2010
@@ -30,6 +30,15 @@
 #ifndef _GL_SYS_WAIT_H
 #define _GL_SYS_WAIT_H
 
+/* Get pid_t.  */
+#include <sys/types.h>
+
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+
 #if !((defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__)
 /* Unix API.  */
 
@@ -71,24 +80,11 @@
 #  define WCOREDUMP(x) ((x) & 0x80)
 # endif
 
-# ifdef __cplusplus
-extern "C" {
-# endif
-
-/* Declarations of functions.  */
-
-# ifdef __cplusplus
-}
-# endif
-
 #else
 /* Native Windows API.  */
 
-# include <process.h> /* for _cwait, WAIT_CHILD */
 # include <signal.h> /* for SIGTERM */
 
-# define waitpid(pid,statusp,options) _cwait (statusp, pid, WAIT_CHILD)
-
 /* The following macros apply to an argument x, that is a status of a process,
    as returned by waitpid() or, equivalently, _cwait() or GetExitCodeProcess().
    This value is simply an 'int', not composed of bit fields.  */
@@ -111,5 +107,29 @@
 
 #endif
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Declarations of functions.  */
+
+#if 1 /* @GNULIB_WAITPID@ */
+# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+_GL_FUNCDECL_SYS (waitpid, pid_t, (pid_t pid, int *statusp, int options));
+# endif
+_GL_CXXALIAS_SYS (waitpid, pid_t, (pid_t pid, int *statusp, int options));
+_GL_CXXALIASWARN (waitpid);
+#elif defined GNULIB_POSIXCHECK
+# undef waitpid
+# if HAVE_RAW_DECL_WAITPID
+_GL_WARN_ON_USE (waitpid, "waitpid is unportable - "
+                 "use gnulib module sys_wait for portability");
+# endif
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* _GL_SYS_WAIT_H */
 #endif /* _GL_SYS_WAIT_H */
--- m4/sys_wait_h.m4.orig       Wed Sep 29 13:15:34 2010
+++ m4/sys_wait_h.m4    Wed Sep 29 13:15:32 2010
@@ -1,4 +1,4 @@
-# sys_wait_h.m4 serial 4
+# sys_wait_h.m4 serial 5
 dnl Copyright (C) 2008-2010 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -10,6 +10,11 @@
 
   dnl <sys/wait.h> is always overridden, because of GNULIB_POSIXCHECK.
   gl_CHECK_NEXT_HEADERS([sys/wait.h])
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[#include <sys/wait.h>]],
+    [waitpid])
 ])
 
 AC_DEFUN([gl_SYS_WAIT_MODULE_INDICATOR],
--- modules/sys_wait.orig       Wed Sep 29 13:15:34 2010
+++ modules/sys_wait    Wed Sep 29 12:58:22 2010
@@ -6,7 +6,10 @@
 m4/sys_wait_h.m4
 
 Depends-on:
+c++defs
 include_next
+warn-on-use
+waitpid
 
 configure.ac:
 gl_SYS_WAIT_H
@@ -17,13 +20,15 @@
 
 # We need the following in order to create <sys/wait.h> when the system
 # has one that is incomplete.
-sys/wait.h: sys_wait.in.h
+sys/wait.h: sys_wait.in.h $(CXXDEFS_H) $(WARN_ON_USE_H)
        $(AM_V_at)$(MKDIR_P) sys
        $(AM_V_GEN)rm -f address@hidden $@ && \
        { echo '/* DO NOT EDIT! GENERATED AUTOMATICALLY! */'; \
          sed -e 's|@''INCLUDE_NEXT''@|$(INCLUDE_NEXT)|g' \
              -e 's|@''PRAGMA_SYSTEM_HEADER''@|@PRAGMA_SYSTEM_HEADER@|g' \
              -e 's|@''NEXT_SYS_WAIT_H''@|$(NEXT_SYS_WAIT_H)|g' \
+             -e '/definitions of _GL_FUNCDECL_RPL/r $(CXXDEFS_H)' \
+             -e '/definition of _GL_WARN_ON_USE/r $(WARN_ON_USE_H)' \
              < $(srcdir)/sys_wait.in.h; \
        } > address@hidden && \
        mv address@hidden $@