https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110574
Bug ID: 110574
Summary: --enable-cstdio=stdio_pure is incompatible with LFS
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
CC: keithp at keithp dot com
Target Milestone: ---
Using --enable-cstdio=stdio_pure on x86_64-pc-linux-gnu results in test
failures:
FAIL: 27_io/basic_filebuf/imbue/char/13171-2.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/12790-3.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/45628-2.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/1-in.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/1-io.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/1-out.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/2-in.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/2-io.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/2-out.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/26777.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/char/4.cc execution test
FAIL: 27_io/basic_filebuf/seekoff/wchar_t/4.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/12790-2.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/12790-3.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/char/1-in.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/char/1-io.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/char/1-out.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/char/2-in.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/char/2-io.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/char/2-out.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/wchar_t/9874.cc execution test
FAIL: 27_io/basic_filebuf/seekpos/wchar_t/9875_seekpos.cc execution test
FAIL: 27_io/basic_filebuf/sgetn/char/2-in.cc execution test
FAIL: 27_io/basic_filebuf/sgetn/char/2-io.cc execution test
FAIL: 27_io/basic_filebuf/sputbackc/char/1-io.cc execution test
FAIL: 27_io/basic_filebuf/sputbackc/char/2-io.cc execution test
FAIL: 27_io/basic_filebuf/sungetc/char/1-io.cc execution test
FAIL: 27_io/basic_filebuf/sungetc/char/2-io.cc execution test
FAIL: 27_io/basic_filebuf/underflow/char/10097.cc execution test
FAIL: 27_io/basic_filebuf/underflow/wchar_t/5.cc execution test
FAIL: 27_io/basic_fstream/53984.cc execution test
FAIL: 27_io/basic_istream/peek/char/6414.cc execution test
FAIL: 27_io/basic_istream/peek/wchar_t/6414.cc execution test
FAIL: 27_io/basic_istream/seekg/char/fstream.cc execution test
FAIL: 27_io/basic_istream/seekg/wchar_t/fstream.cc execution test
FAIL: 27_io/basic_istream/tellg/char/fstream.cc execution test
FAIL: 27_io/basic_istream/tellg/wchar_t/fstream.cc execution test
FAIL: 27_io/objects/wchar_t/12.cc execution test
This seems to be because of code like:
streamoff
__basic_file<char>::seekoff(streamoff __off, ios_base::seekdir __way) throw
()
{
#ifdef _GLIBCXX_USE_LFS
return lseek64(this->fd(), __off, __way);
#else
if (__off > numeric_limits<off_t>::max()
|| __off < numeric_limits<off_t>::min())
return -1L;
#ifdef _GLIBCXX_USE_STDIO_PURE
return fseek(this->file(), __off, __way);
#else
return lseek(this->fd(), __off, __way);
#endif
#endif
If LFS is being used then the STDIO_PURE config is ignored, and we use lseek64
on the file descriptor unconditionally. Then when we read we do respect the
STDIO_PURE config:
streamsize
__basic_file<char>::xsgetn(char* __s, streamsize __n)
{
streamsize __ret;
do
#ifdef _GLIBCXX_USE_STDIO_PURE
__ret = fread(__s, 1, __n, this->file());
#else
__ret = read(this->fd(), __s, __n);
#endif
while (__ret == -1L && errno == EINTR);
return __ret;
}
But now we're seeking on the file descriptor and reading from the FILE. We need
to use fseek before fread.
