Flushes a file directly to disk.
The _commit function forces the operating system to write the file associated with fd to disk. This call ensures that the specified file is flushed immediately, not at the operating system's discretion.
If fd is an invalid file descriptor, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, the function returns -1 and errno is set to EBADF.
For more compatibility information, see Compatibility in the Introduction.