Hi, all:
I used an ofdstream.h written by others:
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#ifndef _OFDSTREAM_H
#define _OFDSTREAM_H
#include <fstream>
#include <ostream>
#include <ext/stdio_filebuf.h>
class ofdstream: public std::ofstream
{
private:
__gnu_cxx::stdio_filebuf< char > m_buf;
int m_fd;
public:
ofdstream( int fd, int bufsize = 4096 );
int fd() const { return( m_fd ); };
};
inline ofdstream::ofdstream( int fd, int bufsize )
#if __GNUC_PREREQ (3,4)
: m_buf( fd, std::ios_base::out, bufsize )
#else
: m_buf( fd, std::ios_base::out, true, bufsize )
#endif
{
//this->init(&m_buf);
std::basic_ios< char >::rdbuf( & m_buf );
}
#endif // _OFDSTREAM_H
------------->>>>>>>>>>>-------------------<<<<<<<<<<<<------------------------
And the below is my test a.cpp:
------------->>>>>>>>>>>-------------------<<<<<<<<<<<<------------------------
#include "fdstream.h"
#include <iostream>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
using namespace std;
int
main()
{
int fd = open("a.log", O_WRONLY|O_CREAT, 0600);
if (fd < 0) {
cerr << "open error" << endl;
exit(1);
}
ofdstream ofs(fd);
ofs << "testtest" << flush;
close(fd);
return 0;
}
------------->>>>>>>>>>>-------------------<<<<<<<<<<<<------------------------
compile and run it:
# g++ -g -o a a.cpp
# ./a
Segmentation fault (core dumped)
# g++ -v
Reading specs from /usr/lib/gcc-lib/i686-pc-linux-gnu/3.2/specs
Configured with: ../gcc-3.2/configure --prefix=/usr --enable-shared
--enable-languages=c,c++ --enable-threads=posix --with-slibdir=/lib
--enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 3.2
The below is backtrace of the core dump:
(gdb) bt
#0 0x40167d46 in free () from /lib/libc.so.6
#1 0x40157de7 in fclose@@GLIBC_2.1 () from /lib/libc.so.6
#2 0x40053ca4 in std::__basic_file<char>::close () from
/usr/lib/libstdc++.so.5
#3 0x4005388f in std::__basic_file<char>::~__basic_file () from
/usr/lib/libstdc++.so.5
#4 0x4008b64f in std::basic_filebuf<char, std::char_traits<char>
::~basic_filebuf () from /usr/lib/libstdc++.so.5
#5 0x08049a5a in ~stdio_filebuf (this=0xbffff9fc) at
/usr/include/c++/3.2/ext/stdio_filebuf.h:115
#6 0x08049778 in ~ofdstream (this=0xbffff970) at a.cpp:19
#7 0x0804969d in main () at a.cpp:25
But if I compile a.cpp with g++ 3.4.4, there is no segmentation fault.
I failed to find and fix the bug.
Is this a bug in libstdc++?
-------------------
Holderlin Zhang
Department of Applied Math., Nankai University
