table of contents
FILENO(3) | Linux Programmer's Manual | FILENO(3) |
NAME¶
fileno - obtain file descriptor of a stdio stream
SYNOPSIS¶
#include <stdio.h>
int fileno(FILE *stream);
fileno():
_POSIX_C_SOURCE
DESCRIPTION¶
The function fileno() examines the argument stream and returns the integer file descriptor used to implement this stream. The file descriptor is still owned by stream and will be closed when fclose(3) is called. Duplicate the file descriptor with dup(2) before passing it to code that might close it.
For the nonlocking counterpart, see unlocked_stdio(3).
RETURN VALUE¶
On success, fileno() returns the file descriptor associated with stream. On failure, -1 is returned and errno is set to indicate the error.
ERRORS¶
- EBADF
- stream is not associated with a file.
ATTRIBUTES¶
For an explanation of the terms used in this section, see attributes(7).
Interface | Attribute | Value |
fileno () | Thread safety | MT-Safe |
CONFORMING TO¶
The function fileno() conforms to POSIX.1-2001 and POSIX.1-2008.
SEE ALSO¶
COLOPHON¶
This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.
2021-03-22 |