# HG changeset patch
# User Bruno Haible <bruno@clisp.org>
# Date 1328008546 -3600
# Node ID 993344da76d0715938c833bfea5d851008006cda
# Parent  5770cc0ba46fa2fd95aee1811edf305ee0f2c088
popen: Make more robust on Windows.

* lib/popen.c: On native Windows, use the _popen based code even if
HAVE_POPEN is set.
* doc/posix-functions/popen.texi: Mention necessity of COMSPEC
environment variable on native Windows.

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2012-01-31  Bruno Haible  <bruno@clisp.org>
+
+	popen: Make more robust on Windows.
+	* lib/popen.c: On native Windows, use the _popen based code even if
+	HAVE_POPEN is set.
+	* doc/posix-functions/popen.texi: Mention necessity of COMSPEC
+	environment variable on native Windows.
+
 2012-01-30  Bruno Haible  <bruno@clisp.org>
 
 	pclose: Fix typo.
diff --git a/doc/posix-functions/popen.texi b/doc/posix-functions/popen.texi
--- a/doc/posix-functions/popen.texi
+++ b/doc/posix-functions/popen.texi
@@ -20,6 +20,9 @@
 Portability problems not fixed by Gnulib:
 @itemize
 @item
+On native Windows platforms, this functions terminates the current process
+with exit code 127 if the environment variable @code{COMSPEC} is not set.
+@item
 Some platforms mistakenly set the close-on-exec bit, then if it is
 cleared by the application, the platform then leaks file descriptors
 from earlier @code{popen} calls into subsequent @code{popen} children:
diff --git a/lib/popen.c b/lib/popen.c
--- a/lib/popen.c
+++ b/lib/popen.c
@@ -21,7 +21,24 @@
 /* Specification.  */
 #include <stdio.h>
 
-#if HAVE_POPEN
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Native Windows API.  */
+
+# include <string.h>
+
+FILE *
+popen (const char *filename, const char *mode)
+{
+  /* Use binary mode by default.  */
+  if (strcmp (mode, "r") == 0)
+    mode = "rb";
+  else if (strcmp (mode, "w") == 0)
+    mode = "wb";
+
+  return _popen (filename, mode);
+}
+
+#else
 
 # include <errno.h>
 # include <fcntl.h>
@@ -33,7 +50,7 @@
 FILE *
 rpl_popen (const char *filename, const char *mode)
 {
-  /* The mingw popen works fine, and all other platforms have fcntl.
+  /* All other platforms have popen and fcntl.
      The bug of the child clobbering its own file descriptors if stdin
      or stdout was closed in the parent can be worked around by
      opening those two fds as close-on-exec to begin with.  */
@@ -83,21 +100,4 @@
   return result;
 }
 
-#else
-/* Native Windows API.  */
-
-# include <string.h>
-
-FILE *
-popen (const char *filename, const char *mode)
-{
-  /* Use binary mode by default.  */
-  if (strcmp (mode, "r") == 0)
-    mode = "rb";
-  else if (strcmp (mode, "w") == 0)
-    mode = "wb";
-
-  return _popen (filename, mode);
-}
-
 #endif