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

       stderr, stdin, stdout - standard I/O streams

SYNOPSIS

       #include <stdio.h>

       extern FILE *stderr, *stdin, *stdout;

DESCRIPTION

       A file with associated buffering is called a stream and is declared to be a pointer to a defined type FILE. The fopen() function shall cre-
       ate  certain  descriptive  data	for a stream and return a pointer to designate the stream in all further transactions. Normally, there are
       three open streams with constant pointers declared in the <stdio.h> header and associated with the standard open files.

       At program start-up, three streams shall be predefined and need not be opened explicitly: standard input (for reading conventional  input),
       standard  output  (for  writing	conventional  output), and standard error (for writing diagnostic output). When opened, the standard error
       stream is not fully buffered; the standard input and standard output streams are fully buffered if and only if the stream can be determined
       not to refer to an interactive device.

       The  following  symbolic  values  in <unistd.h> define the file descriptors that shall be associated with the C-language stdin, stdout, and
       stderr when the application is started:

       STDIN_FILENO
	      Standard input value, stdin. Its value is 0.

       STDOUT_FILENO
	      Standard output value, stdout. Its value is 1.

       STDERR_FILENO
	      Standard error value, stderr. Its value is 2.

       The stderr stream is expected to be open for reading and writing.

RETURN VALUE

       None.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fclose(), feof(), ferror(), fileno(), fopen(), fread(), fseek(), getc(), gets(), popen(), printf(), putc(), puts(), read(),  scanf(),  set-
       buf(), setvbuf(), tmpfile(), ungetc(), vprintf(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>, <unistd.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								 STDIN(3P)