v7 man page for stdio

STDIO(3S)																 STDIO(3S)

NAME
       stdio - standard buffered input/output package

SYNOPSIS
       #include <stdio.h>

       FILE *stdin;
       FILE *stdout;
       FILE *stderr;

DESCRIPTION
       The  functions  described  in  Sections 3S constitute an efficient user-level buffering scheme.	The in-line macros getc and putc(3) handle
       characters quickly.  The higher level routines gets, fgets, scanf, fscanf, fread, puts, fputs, printf, fprintf, fwrite  all  use  getc  and
       putc; they can be freely intermixed.

       A  file	with  associated  buffering  is called a stream, and is declared to be a pointer to a defined type FILE.  Fopen(3) creates certain
       descriptive data for a stream and returns a pointer to designate the stream in all further transactions.  There	are  three  normally  open
       streams with constant pointers declared in the include file and associated with the standard open files:

       stdin	 standard input file
       stdout	 standard output file
       stderr	 standard error file

       A constant `pointer' NULL(0) designates no stream at all.

       An integer constant EOF (-1) is returned upon end of file or error by integer functions that deal with streams.

       Any  routine  that uses the standard input/output package must include the header file <stdio.h> of pertinent macro definitions.  The func-
       tions and constants mentioned in sections labeled 3S are declared in the include file and need no further declaration.  The constants,  and
       the  following `functions' are implemented as macros; redeclaration of these names is perilous: getc, getchar, putc, putchar, feof, ferror,
       fileno.

SEE ALSO
       open(2), close(2), read(2), write(2)

DIAGNOSTICS
       The value EOF is returned uniformly to indicate that a FILE pointer has not been initialized with fopen, input (output) has been  attempted
       on an output (input) stream, or a FILE pointer designates corrupt or otherwise unintelligible FILE data.

																	 STDIO(3S)