User  |  Syst  |  Libr  |  Device  |  Files  |  Other  |  Admin  |  Head  |

---

   fileno.3p    ( 3 )

---

---

Пролог (Prolog)

This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

---

Имя (Name)

fileno — map a stream pointer to a file descriptor

---

Синопсис (Synopsis)

#include <stdio.h>

       int fileno(FILE *stream);

---

Описание (Description)

The fileno() function shall return the integer file descriptor
       associated with the stream pointed to by stream.

---

Возвращаемое значение (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.

---

Ошибки (Error)

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.

       The following sections are informative.

---

Примеры (Examples)

None.

---

Использование в приложениях (Application usage)

None.

---

Обоснование (Rationale)

Without some specification of which file descriptors are
       associated with these streams, it is impossible for an
       application to set up the streams for another application it
       starts with fork() and exec.  In particular, it would not be
       possible to write a portable version of the sh command
       interpreter (although there may be other constraints that would
       prevent that portability).

---

Будущие направления (Future directions)

None.

---

Смотри также (See also)

Section 2.5.1, Interaction of File Descriptors and Standard I/O
       Streams, dirfd(3p), fdopen(3p), fopen(3p), stdin(3p)

       The Base Definitions volume of POSIX.1‐2017, stdio.h(0p)

---