The GCC site says under "what we do not want":
"Bugs in releases or snapshots of GCC not issued by the GNU Project.
Report them to whoever provided you with the release."
So until I get enough time to build a development snapshot, I won't be
submitting this directly to the gcc folks. I did download some of the
source for gcc 4.5.0. My co-worker Brad and I were looking at it and
found what may be the problem.
libstdc++-v3/config/io/basic_file_stdio.cc:
__basic_file<char>*
__basic_file<char>::close()
{
__basic_file* __ret = static_cast<__basic_file*>(NULL);
if (this->is_open())
{
int __err = 0;
if (_M_cfile_created)
{
// In general, no need to zero errno in advance if checking
// for error first. However, C89/C99 (at variance with IEEE
// 1003.1, f.i.) do not mandate that fclose must set errno
// upon error.
errno = 0;
do
__err = fclose(_M_cfile);
while (__err && errno == EINTR);
}
_M_cfile = 0;
if (!__err)
__ret = this;
}
return __ret;
}
It appears errno should be saved in a temporary variable and restored
before the return if it did not change.
** Description changed:
Binary package hint: gcc-4.4
-
The errno man page says:
"errno is never set to zero by any system call or library function."
However the attached test code proves otherwise.
Compile with "g++ -o test test.cpp"
Run test. Observe that errno changes from 4 to 0.
Code "passes" (ie - does not change to 0) with gcc version 3.3.3
20040412 (Red Hat Linux 3.3.3-7)
Code "fails" with:
gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
- gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
- gcc version 4.3.2 (Debian 4.3.2-1.1)
+ gcc version 4.3.3 (Ubuntu 4.3.3-5ubuntu4)
+ gcc version 4.3.2 (Debian 4.3.2-1.1)
The details:
I'm in the process of porting some old code running in a Fedora Core 2
environment to the Ubuntu 10.04 environment, and I came upon an issue where
errno is getting cleared. The attached test.cpp is a (hopefully) minimized
test case to prove the bug.
lsb_release -rd
Description: Ubuntu 10.04 LTS
Release: 10.04
gcc -v
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
4.4.3-4ubuntu5' --with-bugurl=file:///usr/share/doc/gcc-4.4/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--enable-multiarch --enable-linker-build-id --with-system-zlib
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-include-dir=/usr/include/c++/4.4 --program-suffix=-4.4 --enable-nls
--enable-clocale=gnu --enable-libstdcxx-debug --enable-plugin --enable-objc-gc
--enable-targets=all --disable-werror --with-arch-32=i486 --with-tune=generic
--enable-checking=release --build=i486-linux-gnu --host=i486-linux-gnu
--target=i486-linux-gnu
Thread model: posix
- gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
+ gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5)
apt-cache policy libstdc++6
libstdc++6:
- Installed: 4.4.3-4ubuntu5
- Candidate: 4.4.3-4ubuntu5
- Version table:
- *** 4.4.3-4ubuntu5 0
- 500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages
- 100 /var/lib/dpkg/status
+ Installed: 4.4.3-4ubuntu5
+ Candidate: 4.4.3-4ubuntu5
+ Version table:
+ *** 4.4.3-4ubuntu5 0
+ 500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages
+ 100 /var/lib/dpkg/status
apt-cache policy gcc
gcc:
- Installed: 4:4.4.3-1ubuntu1
- Candidate: 4:4.4.3-1ubuntu1
- Version table:
- *** 4:4.4.3-1ubuntu1 0
- 500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages
- 100 /var/lib/dpkg/status
+ Installed: 4:4.4.3-1ubuntu1
+ Candidate: 4:4.4.3-1ubuntu1
+ Version table:
+ *** 4:4.4.3-1ubuntu1 0
+ 500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages
+ 100 /var/lib/dpkg/status
Tomorrow I'll report this to gcc directly using their bugzilla. But I
wanted the Ubuntu team to know first, since it's their versions of gcc
I'm using. :)
Let me know if there's anything else I can do to help,
Chris Fester
--
errno cleared by ofstream close or string conversion
https://bugs.launchpad.net/bugs/598299
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