Gets the length of a file.
long _filelength( int fd ); __int64 _filelengthi64( int fd );
Target the file descriptor.
Both _filelength and _filelengthi64 return the file length, in bytes, of the target file associated with fd. If fd is an invalid file descriptor, this function invokes the invalid parameter handler, as described in Parameter Validation. If execution is allowed to continue, both functions return -1L to indicate an error and set errno to EBADF.
By default, this function's global state is scoped to the application. To change this, see Global state in the CRT.
For more compatibility information, see Compatibility.
See the example for _chsize.