Synopsis

#include <stdio.h>

int fileno(FILE *stream);

Status

Partially implemented

Conformance

IEEE Std 1003.1-2017

Description

The fileno() function maps a stream pointer to a file descriptor associated with the stream pointed to by stream.

Return value

Upon successful completion, fileno() shall return the integer value of the file descriptor associated with stream. Otherwise, the value -1 shall be returned and errno set to indicate the error.

Errors

The fileno() function shall fail if:

  • EBADF - The stream is not associated with a file.

The fileno() function may fail if:

  • EBADF - The file descriptor underlying stream is not a valid file descriptor.

Tests

Untested

Known bugs

None

See Also

  1. Standard library functions
  2. Table of Contents