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[Fwd: Re: libstdc++/8504: ios::app + pipes]
- From: Paolo Carlini <pcarlini at unitus dot it>
- To: gcc-gnats at gcc dot gnu dot org, gcc-bugs at gcc dot gnu dot org, gcc-prs at gcc dot gnu dot org, nobody at gcc dot gnu dot org
- Date: Mon, 18 Nov 2002 15:31:36 +0100
- Subject: [Fwd: Re: libstdc++/8504: ios::app + pipes]
Here are some more details.
Running my example in the debugger I found that the relevant code in
source file libstdc++-v3/config/io/basic_file_stdio.cc from gcc 3.2
looks like:
115 __basic_file<char>*
116 __basic_file<char>::open(const char* __name, ios_base::openmode __mode,
117 int /*__prot*/)
118 {
[...]
128 if ((_M_cfile = fopen(__name, __c_mode)))
In an attempt to reproduce the problem, I've written the following code:
#include <stdio.h>
int main() {
if (!fopen("/tmp/pipe", "a"))
perror("/tmp/pipe");
}
This code fails on Solaris and IRIX. It succeeds on Linux:
$ uname -sr
SunOS 5.8
$ g++ -v
Reading specs from
/usr/local/gcc/bin/../lib/gcc-lib/sparc-sun-solaris2.8/3.2/specs
Configured with: ../gcc-3.2/configure --prefix=/usr/local/gcc-3.2
--with-as=/usr/local/binutils/bin/as --with-ld=/usr/local/binutils/bin/ld
Thread model: posix
gcc version 3.2
$ g++ -g -o foo foo.cc
$ ./foo
/tmp/pipe: Illegal seek
$
$ uname -sr
Linux 2.4.18-14
$ g++ -v
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--disable-checking --host=i386-redhat-linux --with-system-zlib
--enable-__cxa_atexit
Thread model: posix
gcc version 3.2 200020903 (Red Hat Linux 8.0 3.2-7)
$ g++ -g -o foo foo.cc
$ ./foo
$
So it's really a question of fopen(..., "a") not working on pipes on
Solaris and IRIX. Somehow gcc 2.95.3 used to work around this issue.
Regards,
--
Dimitri
http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8504