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#include <stdio.h>
#include <unistd.h>
#include <atomic.h>
#include <io.h>
#include <errno.h>
#include <string.h>
int fflush(FILE *stream)
{
// Handle NULL stream - flush all open streams
if (stream == NULL) {
// TODO: Implement flushing all open streams
// For now, just return success
return 0;
}
// Nothing to flush if buffer is empty
if (stream->buf_len == 0) {
return 0;
}
// Handle special case of invalid file descriptor
if (stream->fd == -1) {
stream->buf_len = 0;
return 0;
}
// Check if stream is in error state
if (stream->flags & _IO_ERR) {
errno = EIO;
return EOF;
}
// Check if stream is writable
if ((stream->flags & O_ACCMODE) == O_RDONLY) {
errno = EBADF;
return EOF;
}
LIBC_LOCK(stream->lock);
size_t bytes_to_write = stream->buf_len;
size_t total_written = 0;
char *buf_ptr = stream->buf;
// Write all buffered data
while (total_written < bytes_to_write) {
ssize_t result = write(stream->fd, buf_ptr + total_written,
bytes_to_write - total_written);
if (result < 0) {
// Write error occurred
stream->flags |= _IO_ERR;
LIBC_UNLOCK(stream->lock);
return EOF;
}
if (result == 0) {
// No progress made (shouldn't happen with regular
// files)
break;
}
total_written += result;
}
// Update buffer state
if (total_written == bytes_to_write) {
// All data was written successfully
stream->buf_len = 0;
stream->buf_pos = 0;
} else {
// Partial write - move remaining data to beginning of buffer
size_t remaining = bytes_to_write - total_written;
memmove(stream->buf, stream->buf + total_written, remaining);
stream->buf_len = remaining;
stream->buf_pos = 0;
}
LIBC_UNLOCK(stream->lock);
// Return success if all data was written, error otherwise
return (total_written == bytes_to_write) ? 0 : EOF;
}
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