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 create 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() , setbuf() , 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 Technology -- 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 .