Fix a flush issue on libstdc++

This commit is contained in:
Victor Zverovich
2025-03-30 09:55:13 -07:00
parent 2f58430573
commit 5199e0f885
2 changed files with 32 additions and 3 deletions

View File

@ -1526,9 +1526,8 @@ template <typename F> class glibc_file : public file_base<F> {
}
void init_buffer() {
if (this->file_->_IO_write_ptr) return;
if (this->file_->_IO_write_ptr < this->file_->_IO_write_end) return;
// Force buffer initialization by placing and removing a char in a buffer.
assume(this->file_->_IO_write_ptr >= this->file_->_IO_write_end);
putc_unlocked(0, this->file_);
--this->file_->_IO_write_ptr;
}

View File

@ -540,7 +540,7 @@ TEST(file_test, line_buffering) {
reader.join();
}
# endif // _WIN32
# endif // _WIN32
TEST(file_test, buffer_boundary) {
auto pipe = fmt::pipe();
@ -559,4 +559,34 @@ TEST(file_test, buffer_boundary) {
EXPECT_STREQ(fgets(buf, sizeof(buf), read_end.get()), "1234 567");
}
TEST(file_test, io_putting) {
auto pipe = fmt::pipe();
auto read_end = pipe.read_end.fdopen("r");
auto write_end = pipe.write_end.fdopen("w");
size_t read_size = 0;
auto reader = std::thread([&]() {
size_t n = 0;
do {
char buf[4096] = {};
n = fread(buf, 1, sizeof(buf), read_end.get());
read_size += n;
} while (n != 0);
});
// This initialize buffers but doesn't set _IO_CURRENTLY_PUTTING.
fseek(write_end.get(), 0, SEEK_SET);
size_t write_size = 0;
for (int i = 0; i <= 20000; ++i) {
auto s = fmt::format("{}\n", i);
fmt::print(write_end.get(), "{}", s);
write_size += s.size();
}
write_end.close();
reader.join();
EXPECT_EQ(read_size, write_size);
}
#endif // FMT_USE_FCNTL