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 .