test-perror: relax test to ignore cygwin bug

glibc was not the only platform where fprintf(fopen(,"r"))
fails to detect errors; cygwin 1.7.9 is another culprit
(although it will be fixed for 1.7.10), and I suspect that
several other platforms were failing perror2 for the same
reason.

At this point, there are so many functions affected, and
the way to avoid the bug is easy enough (don't pass bogus
streams to output-producing functions), that I'm not worried
about fixing things other than to document them.

* tests/test-perror2.c (main): Relax test on requiring detection
of stream errors, and use unbuffered stream.
* doc/posix-functions/dprintf.texi (dprintf): Document bug.
* doc/posix-functions/fprintf.texi (fprintf): Likewise.
* doc/posix-functions/fputc.texi (fputc): Likewise.
* doc/posix-functions/fputs.texi (fputs): Likewise.
* doc/posix-functions/fputws.texi (fputws): Likewise.
* doc/posix-functions/fwprintf.texi (fwprintf): Likewise.
* doc/posix-functions/fwrite.texi (fwrite): Likewise.
* doc/posix-functions/getopt.texi (getopt): Likewise.
* doc/posix-functions/perror.texi (perror): Likewise.
* doc/posix-functions/printf.texi (printf): Likewise.
* doc/posix-functions/psiginfo.texi (psiginfo): Likewise.
* doc/posix-functions/psignal.texi (psignal): Likewise.
* doc/posix-functions/putc.texi (putc): Likewise.
* doc/posix-functions/putc_unlocked.texi (putc_unlocked):
Likewise.
* doc/posix-functions/putchar.texi (putchar): Likewise.
* doc/posix-functions/putchar_unlocked.texi (putchar_unlocked):
Likewise.
* doc/posix-functions/puts.texi (puts): Likewise.
* doc/posix-functions/putwc.texi (putwc): Likewise.
* doc/posix-functions/putwchar.texi (putwchar): Likewise.
* doc/posix-functions/vdprintf.texi (vdprintf): Likewise.
* doc/posix-functions/vfprintf.texi (vfprintf): Likewise.
* doc/posix-functions/vfwprintf.texi (vfwprintf): Likewise.
* doc/posix-functions/vprintf.texi (vprintf): Likewise.
* doc/posix-functions/vwprintf.texi (vwprintf): Likewise.
* doc/posix-functions/wordexp.texi (wordexp): Likewise.
* doc/posix-functions/wprintf.texi (wprintf): Likewise.

Signed-off-by: Eric Blake <eblake@redhat.com>

26 files changed, 84 insertions, 7 deletions

diff --git a/doc/posix-functions/dprintf.texi b/doc/posix-functions/dprintf.texi
index dc39022926..e267cda461 100644
--- a/doc/posix-functions/dprintf.texi
+++ b/doc/posix-functions/dprintf.texi
@@ -24,4 +24,8 @@ glibc-2.3.6.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/fprintf.texi b/doc/posix-functions/fprintf.texi
index 44bcca3768..3948018b6c 100644
--- a/doc/posix-functions/fprintf.texi
+++ b/doc/posix-functions/fprintf.texi
@@ -86,5 +86,5 @@ Portability problems not fixed by Gnulib:
 @item
 Attempting to write to a read-only stream fails with @code{EOF} but
 does not set the error flag for @code{ferror} on some platforms:
-glibc 2.13.
+glibc 2.13, cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/fputc.texi b/doc/posix-functions/fputc.texi
index 9d6c9fd29c..1b5ba7c2b5 100644
--- a/doc/posix-functions/fputc.texi
+++ b/doc/posix-functions/fputc.texi
@@ -28,4 +28,8 @@ Portability problems not fixed by Gnulib:
 @item
 On Windows platforms (excluding Cygwin), this function does not set @code{errno}
 upon failure.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/fputs.texi b/doc/posix-functions/fputs.texi
index 7fc4bf5311..a7e79d4862 100644
--- a/doc/posix-functions/fputs.texi
+++ b/doc/posix-functions/fputs.texi
@@ -28,4 +28,8 @@ Portability problems not fixed by Gnulib:
 @item
 On Windows platforms (excluding Cygwin), this function does not set @code{errno}
 upon failure.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/fputws.texi b/doc/posix-functions/fputws.texi
index f3b2b4e4b1..c842488d0a 100644
--- a/doc/posix-functions/fputws.texi
+++ b/doc/posix-functions/fputws.texi
@@ -18,4 +18,8 @@ IRIX 5.3, Solaris 2.5.1, Cygwin 1.5.x, BeOS.
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/fwprintf.texi b/doc/posix-functions/fwprintf.texi
index 79ffc25ad5..d245890ead 100644
--- a/doc/posix-functions/fwprintf.texi
+++ b/doc/posix-functions/fwprintf.texi
@@ -18,4 +18,8 @@ NetBSD 3.0, OpenBSD 3.8, HP-UX 11.00, IRIX 6.5, Solaris 2.6, Cygwin 1.5.x, Inter
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/fwrite.texi b/doc/posix-functions/fwrite.texi
index 20f7fb8100..c03a70ccab 100644
--- a/doc/posix-functions/fwrite.texi
+++ b/doc/posix-functions/fwrite.texi
@@ -28,4 +28,8 @@ Portability problems not fixed by Gnulib:
 @item
 On Windows platforms (excluding Cygwin), this function does not set @code{errno}
 upon failure.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/getopt.texi b/doc/posix-functions/getopt.texi
index 4067295ca1..bab4922e19 100644
--- a/doc/posix-functions/getopt.texi
+++ b/doc/posix-functions/getopt.texi
@@ -67,4 +67,8 @@ causing a reset by setting it non-zero, although it does not
 necessarily re-read @env{POSIXLY_CORRECT}.  Solaris @code{getopt} does
 not support either reset method, but does not maintain state that
 needs the extra level of reset.
+@item
+On some platforms, this function does not set the stream error
+indicator on attempts to write to a read-only stream:
+glibc 2.13, Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/perror.texi b/doc/posix-functions/perror.texi
index 167cf39aea..13231e95ea 100644
--- a/doc/posix-functions/perror.texi
+++ b/doc/posix-functions/perror.texi
@@ -23,7 +23,7 @@ Portability problems not fixed by Gnulib:
 @item
 POSIX requires that this function set the stream error bit (detected
 by @code{ferror}) on write failure, but not all platforms do this:
-glibc 2.13.
+glibc 2.13, cygwin 1.7.9.
 @item
 POSIX requires that this function not alter stream orientation, but
 the gnulib replacement locks in byte orientation and fails on wide
diff --git a/doc/posix-functions/printf.texi b/doc/posix-functions/printf.texi
index 8fc8cb0922..db7218b401 100644
--- a/doc/posix-functions/printf.texi
+++ b/doc/posix-functions/printf.texi
@@ -86,5 +86,5 @@ Portability problems not fixed by Gnulib:
 @item
 Attempting to write to a read-only stream fails with @code{EOF} but
 does not set the error flag for @code{ferror} on some platforms:
-glibc 2.13.
+glibc 2.13, cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/psiginfo.texi b/doc/posix-functions/psiginfo.texi
index 2e940c0d8a..a0f530bcc5 100644
--- a/doc/posix-functions/psiginfo.texi
+++ b/doc/posix-functions/psiginfo.texi
@@ -14,5 +14,6 @@ Portability problems not fixed by Gnulib:
 @itemize
 @item
 This function is missing on some platforms:
-glibc 2.3.6, MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, OSF/1 5.1, Cygwin, mingw, Interix 3.5, BeOS.
+glibc 2.3.6, MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, AIX
+5.1, HP-UX 11, OSF/1 5.1, Cygwin 1.7.9, mingw, Interix 3.5, BeOS.
 @end itemize
diff --git a/doc/posix-functions/psignal.texi b/doc/posix-functions/psignal.texi
index 167794946c..75e6ed882f 100644
--- a/doc/posix-functions/psignal.texi
+++ b/doc/posix-functions/psignal.texi
@@ -14,5 +14,5 @@ Portability problems not fixed by Gnulib:
 @itemize
 @item
 This function is missing on some platforms:
-HP-UX 11, Cygwin, mingw, Interix 3.5, BeOS.
+HP-UX 11, Cygwin 1.7.9, mingw, Interix 3.5, BeOS.
 @end itemize
diff --git a/doc/posix-functions/putc.texi b/doc/posix-functions/putc.texi
index d156461ace..c6a815e3ee 100644
--- a/doc/posix-functions/putc.texi
+++ b/doc/posix-functions/putc.texi
@@ -28,4 +28,8 @@ Portability problems not fixed by Gnulib:
 @item
 On Windows platforms (excluding Cygwin), this function does not set @code{errno}
 upon failure.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/putc_unlocked.texi b/doc/posix-functions/putc_unlocked.texi
index 0c3381e20a..4fbf3c4cf8 100644
--- a/doc/posix-functions/putc_unlocked.texi
+++ b/doc/posix-functions/putc_unlocked.texi
@@ -15,4 +15,8 @@ Portability problems not fixed by Gnulib:
 @item
 This function is missing on some platforms:
 mingw.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/putchar.texi b/doc/posix-functions/putchar.texi
index aeb6b4307c..2ded45a2ae 100644
--- a/doc/posix-functions/putchar.texi
+++ b/doc/posix-functions/putchar.texi
@@ -28,4 +28,8 @@ Portability problems not fixed by Gnulib:
 @item
 On Windows platforms (excluding Cygwin), this function does not set @code{errno}
 upon failure.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/putchar_unlocked.texi b/doc/posix-functions/putchar_unlocked.texi
index 5bf55b3838..bc9c3b03de 100644
--- a/doc/posix-functions/putchar_unlocked.texi
+++ b/doc/posix-functions/putchar_unlocked.texi
@@ -15,4 +15,8 @@ Portability problems not fixed by Gnulib:
 @item
 This function is missing on some platforms:
 mingw.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/puts.texi b/doc/posix-functions/puts.texi
index ef350ac1b1..31e3f0e410 100644
--- a/doc/posix-functions/puts.texi
+++ b/doc/posix-functions/puts.texi
@@ -28,4 +28,8 @@ Portability problems not fixed by Gnulib:
 @item
 On Windows platforms (excluding Cygwin), this function does not set @code{errno}
 upon failure.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/putwc.texi b/doc/posix-functions/putwc.texi
index 82a8a962d5..b624b251e5 100644
--- a/doc/posix-functions/putwc.texi
+++ b/doc/posix-functions/putwc.texi
@@ -18,4 +18,8 @@ IRIX 5.3, Solaris 2.5.1, Cygwin 1.5.x, BeOS.
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/putwchar.texi b/doc/posix-functions/putwchar.texi
index 985759acd2..28930c47ae 100644
--- a/doc/posix-functions/putwchar.texi
+++ b/doc/posix-functions/putwchar.texi
@@ -18,4 +18,8 @@ IRIX 5.3, Solaris 2.5.1, Cygwin 1.5.x, BeOS.
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/vdprintf.texi b/doc/posix-functions/vdprintf.texi
index 20a6ef75c5..8b06c3e3ab 100644
--- a/doc/posix-functions/vdprintf.texi
+++ b/doc/posix-functions/vdprintf.texi
@@ -42,4 +42,8 @@ BeOS.
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/vfprintf.texi b/doc/posix-functions/vfprintf.texi
index c6fab25ed7..4999fb5b23 100644
--- a/doc/posix-functions/vfprintf.texi
+++ b/doc/posix-functions/vfprintf.texi
@@ -86,5 +86,5 @@ Portability problems not fixed by Gnulib:
 @item
 Attempting to write to a read-only stream fails with @code{EOF} but
 does not set the error flag for @code{ferror} on some platforms:
-glibc 2.13.
+glibc 2.13, cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/vfwprintf.texi b/doc/posix-functions/vfwprintf.texi
index e018cf5901..143704b4b4 100644
--- a/doc/posix-functions/vfwprintf.texi
+++ b/doc/posix-functions/vfwprintf.texi
@@ -18,4 +18,8 @@ NetBSD 3.0, OpenBSD 3.8, HP-UX 11.00, IRIX 6.5, Solaris 2.6, Cygwin 1.5.x, Inter
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/vprintf.texi b/doc/posix-functions/vprintf.texi
index 21d4bc60f1..7534e01c0e 100644
--- a/doc/posix-functions/vprintf.texi
+++ b/doc/posix-functions/vprintf.texi
@@ -86,5 +86,5 @@ Portability problems not fixed by Gnulib:
 @item
 Attempting to write to a read-only stream fails with @code{EOF} but
 does not set the error flag for @code{ferror} on some platforms:
-glibc 2.13.
+glibc 2.13, cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/vwprintf.texi b/doc/posix-functions/vwprintf.texi
index e82834a565..9f3e3b88de 100644
--- a/doc/posix-functions/vwprintf.texi
+++ b/doc/posix-functions/vwprintf.texi
@@ -22,4 +22,8 @@ platforms: Cygwin 1.5.x.
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/wordexp.texi b/doc/posix-functions/wordexp.texi
index f5d9eafdb9..6787200127 100644
--- a/doc/posix-functions/wordexp.texi
+++ b/doc/posix-functions/wordexp.texi
@@ -15,4 +15,8 @@ Portability problems not fixed by Gnulib:
 @item
 This function is missing on some platforms:
 MacOS X 10.3, OpenBSD 3.8, IRIX 5.3, Cygwin 1.5.x, mingw, Interix 3.5, BeOS.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize
diff --git a/doc/posix-functions/wprintf.texi b/doc/posix-functions/wprintf.texi
index 885dd8b015..330ca23b19 100644
--- a/doc/posix-functions/wprintf.texi
+++ b/doc/posix-functions/wprintf.texi
@@ -22,4 +22,8 @@ platforms: Cygwin 1.5.x.
 @item
 On AIX and Windows platforms, @code{wchar_t} is a 16-bit type and therefore cannot
 accommodate all Unicode characters.
+@item
+On some platforms, this function does not set @code{errno} or the
+stream error indicator on attempts to write to a read-only stream:
+Cygwin 1.7.9.
 @end itemize