On 2026-07-25 19:40, Bruno Haible wrote:
Paul Eggert wrote:
+#if defined __FILC__
+ if (lenbuf > INT_MAX)
+ lenbuf = INT_MAX;
+#endif
... Should Fil-C be listed as
buggy in doc/posix-functions/snprintf.texi,
doc/posix-functions/vsnprintf.texi, next to other platforms that
mishandle the sizes INT_MAX + 1u (Solaris, z/OS) or INT_MAX + 2u
(FreeBSD, OpenBSD, NetBSD, macOS)?
Yes. When lenbuf has the value INT_MAX + 1, the vasnprintf call fails;
when it has the value INT_MAX, the vasnprintf call succeeds.
I'm a little puzzled, as my question was about snprintf and vsnprintf,
not about vasnprintf. However, assuming that you meant snprintf and
vasnprintf I installed the attached patch. As the patch mentions I
wasn't sure where to put Fil-C (and z/OS) in the Supported Platforms
list but I gave it a guess.
Something like the attacheded untest patch, perhaps, which I stole from
lib/vasnprintf.c?
No, none of the three parts would work.
Oh, I see now see a mistake in my patch. I thought those were calls to
snprintf and vsnprintf, but they are actually calls to a vasnprintf-like
function.
But I'm still puzzled. I thought vasnprintf was supplied by Gnulib and
so does not have the INT_MAX limitation. If so, why limit sizes to
INT_MAX when calling vasnprintf?
Because of the Fil-C problem you mention (that I assume is actually with
snprintf and vsnprintf), should lib/vasnprintf.c's USE_SNPRINTF be 0 if
Lib-C is in use? I'm thinking that would work around the Lib-C bug more
generally, without the need for INT_MAX #ifdefs in callers.From cf2d119406a4c5bbf741a505a397d7f5dae0e216 Mon Sep 17 00:00:00 2001
From: Paul Eggert <[email protected]>
Date: Sun, 26 Jul 2026 11:43:06 -0700
Subject: [PATCH] snprintf, vsnprintf: update doc
* doc/gnulib-intro.texi (Supported Platforms):
Also mention z/OS, Fil-C. Not sure where they should be listed
but I gave it a guess.
* doc/posix-functions/snprintf.texi (snprintf):
* doc/posix-functions/vsnprintf.texi (vsnprintf):
Also mention Fil-C bug.
---
ChangeLog | 10 ++++++++++
doc/gnulib-intro.texi | 4 ++++
doc/posix-functions/snprintf.texi | 2 +-
doc/posix-functions/vsnprintf.texi | 2 +-
4 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 7a5d11b2c9..8fb1fccc2c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2026-07-26 Paul Eggert <[email protected]>
+
+ snprintf, vsnprintf: update doc
+ * doc/gnulib-intro.texi (Supported Platforms):
+ Also mention z/OS, Fil-C. Not sure where they should be listed
+ but I gave it a guess.
+ * doc/posix-functions/snprintf.texi (snprintf):
+ * doc/posix-functions/vsnprintf.texi (vsnprintf):
+ Also mention Fil-C bug.
+
2026-07-25 Bruno Haible <[email protected]>
tests: Avoid some runtime errors with Fil-C.
diff --git a/doc/gnulib-intro.texi b/doc/gnulib-intro.texi
index b7375f2059..8e94c8dfd5 100644
--- a/doc/gnulib-intro.texi
+++ b/doc/gnulib-intro.texi
@@ -197,6 +197,8 @@ glibc on kFreeBSD is rarely tested.
@item
@c There is Alpine Linux 3.19, and also musl-gcc on Ubuntu.
musl libc on Linux is occasionally tested.
+@item
+Fil-C on Linux is occasionally tested.
@end itemize
@item
macOS@. In versions 12.5, it's occasionally tested. In version
@@ -238,6 +240,8 @@ The versions of Windows that are supported are Windows 10 and newer.
@item
GNU Hurd 0.9 is rarely tested.
@item
+z/OS is not tested.
+@item
Minix 3.3.0 is no longer tested.
@item
Haiku is no longer tested.
diff --git a/doc/posix-functions/snprintf.texi b/doc/posix-functions/snprintf.texi
index e05b89ce49..23dd6704fa 100644
--- a/doc/posix-functions/snprintf.texi
+++ b/doc/posix-functions/snprintf.texi
@@ -140,7 +140,7 @@ Portability problems not fixed by Gnulib:
@item
This function fails if the buffer size exceeds @code{INT_MAX},
even if the resulting string length would fit in @code{int}:
-NetBSD, Solaris, z/OS.
+NetBSD, Solaris, z/OS, Fil-C.
@item
This function fails if the buffer size exceeds @code{INT_MAX + 1u},
even if the resulting string length would fit in @code{int}:
diff --git a/doc/posix-functions/vsnprintf.texi b/doc/posix-functions/vsnprintf.texi
index 27f3efc5d8..8a6ca05706 100644
--- a/doc/posix-functions/vsnprintf.texi
+++ b/doc/posix-functions/vsnprintf.texi
@@ -138,7 +138,7 @@ Portability problems not fixed by Gnulib:
@item
This function fails if the buffer size exceeds @code{INT_MAX},
even if the resulting string length would fit in @code{int}:
-NetBSD, Solaris, z/OS.
+NetBSD, Solaris, z/OS, Fil-C.
@item
This function fails if the buffer size exceeds @code{INT_MAX + 1u},
even if the resulting string length would fit in @code{int}:
--
2.53.0
