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libstdc++/10063: Regression: stdio_filebuf broken
- From: peturr02 at ru dot is
- To: gcc-gnats at gcc dot gnu dot org
- Date: 13 Mar 2003 19:33:32 -0000
- Subject: libstdc++/10063: Regression: stdio_filebuf broken
- Reply-to: peturr02 at ru dot is
>Number: 10063
>Category: libstdc++
>Synopsis: Regression: stdio_filebuf broken
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Thu Mar 13 19:36:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator: peturr02 at ru dot is
>Release: gcc 3.4 cvs from 20030312
>Organization:
>Environment:
Red Hat Linux 8.0
>Description:
stdio_filebuf on current mainline now bypasses the FILE* used to construct it and uses the underlying file descriptor. This breaks any program that does I/O on a FILE* before constructing a stdio_filebuf from it.
>How-To-Repeat:
See attachment.
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
----gnatsweb-attachment----
Content-Type: text/plain; name="stdiobug.cc"
Content-Disposition: inline; filename="stdiobug.cc"
#include <ext/stdio_filebuf.h>
#include <cstdio>
#include <fstream>
#undef NDEBUG
#include <cassert>
void test1()
{
using namespace std;
FILE* file = fopen("tmp", "w");
putc('0', file);
putc('1', file);
{
using namespace __gnu_cxx;
stdio_filebuf<char> sbuf (file, ios_base::out);
sbuf.sputc('2');
sbuf.sputc('3');
}
putc('4', file);
fclose(file);
filebuf fbuf;
fbuf.open("tmp", ios_base::in);
char buf[10];
streamsize n = fbuf.sgetn(buf, sizeof(buf));
fbuf.close();
assert(n == 5);
assert(!memcmp(buf, "01234", 5));
}
void test2()
{
using namespace std;
filebuf fbuf;
fbuf.open("tmp", ios_base::out | ios_base::trunc);
fbuf.sputn("01234", 5);
fbuf.close();
FILE* file = fopen("tmp", "r");
int c = getc(file);
assert(c == '0');
c = getc(file);
assert(c == '1');
{
using namespace __gnu_cxx;
stdio_filebuf<char> sbuf (file, ios_base::in);
c = sbuf.sbumpc();
assert(c == '2');
c = sbuf.sbumpc();
assert(c == '3');
c = sbuf.sbumpc();
assert(c == '4');
c = sbuf.sgetc();
assert(c == EOF);
}
fclose(file);
}
int main()
{
test1();
test2();
return 0;
}