Login or Register to Ask a Question and Join Our Community

Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

fileno(3p) [centos man page]

FILENO(3P)						     POSIX Programmer's Manual							FILENO(3P)

PROLOG

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

NAME

       fileno - map a stream pointer to a file descriptor

SYNOPSIS

       #include <stdio.h>

       int fileno(FILE *stream);

DESCRIPTION

       The fileno() function shall return the integer 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 may fail if:

       EBADF  The stream argument is not a valid stream.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

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).

FUTURE DIRECTIONS

       None.

SEE ALSO

       Interaction  of File Descriptors and Standard I/O Streams, fdopen(), fopen(), stdin(), the Base Definitions volume of IEEE Std 1003.1-2001,
       <stdio.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								FILENO(3P)

Check Out this Related Man Page

GETWC(3P)						     POSIX Programmer's Manual							 GETWC(3P)

PROLOG

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

NAME

       getwc - get a wide character from a stream

SYNOPSIS

       #include <stdio.h>
       #include <wchar.h>

       wint_t getwc(FILE *stream);

DESCRIPTION

       The getwc() function shall be equivalent to fgetwc(), except that if it is implemented as a macro it may evaluate stream more than once, so
       the argument should never be an expression with side effects.

RETURN VALUE

       Refer to fgetwc().

ERRORS

       Refer to fgetwc().

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       Since  it may be implemented as a macro, getwc() may treat incorrectly a stream argument with side effects. In particular, getwc(*f++) does
       not necessarily work as expected.  Therefore, use of this function is not recommended; fgetwc() should be used instead.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fgetwc(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>, <wchar.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								 GETWC(3P)
Man Page