2.11BSD#431 - /usr/man/cat3/stdio.0

STDIO(3S)	    UNIX Programmer's Manual		STDIO(3S)


NAME
     stdio - standard buffered input/output package

SYNOPSIS
     #include <stdio.h>

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

DESCRIPTION
     The functions described in section 3S constitute a user-
     level buffering scheme.  The in-line macros getc and
     putc(3S) handle characters quickly.  The higher level rou-
     tines 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(3S)
     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 stan-
     dard 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 defini-
     tions.  The functions 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), fread(3S), fseek(3S),
     f*(3S)

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


Printed 11/26/99	  May 13, 1986				1


STDIO(3S)	    UNIX Programmer's Manual		STDIO(3S)


     pointer designates corrupt or otherwise unintelligible FILE
     data.

     For purposes of efficiency, this implementation of the stan-
     dard library has been changed to line buffer output to a
     terminal by default and attempts to do this transparently by
     flushing the output whenever a read(2) from the standard
     input is necessary.  This is almost always transparent, but
     may cause confusion or malfunctioning of programs which use
     standard i/o routines but use read(2) themselves to read
     from the standard input.

     In cases where a large amount of computation is done after
     printing part of a line on an output terminal, it is neces-
     sary to fflush(3S) the standard output before going off and
     computing so that the output will appear.

BUGS
     The standard buffered functions do not interact well with
     certain other library and system functions, especially vfork
     and abort.

LIST OF FUNCTIONS
     Name	 Appears on Page    Description
     clearerr	   ferror.3s	stream status inquiries
     fclose	   fclose.3s	close or flush a stream
     fdopen	   fopen.3s	open a stream
     feof	   ferror.3s	stream status inquiries
     ferror	   ferror.3s	stream status inquiries
     fflush	   fclose.3s	close or flush a stream
     fgetc	   getc.3s	get character or word from stream
     fgets	   gets.3s	get a string from a stream
     fileno	   ferror.3s	stream status inquiries
     fopen	   fopen.3s	open a stream
     fprintf	   printf.3s	formatted output conversion
     fputc	   putc.3s	put character or word on a stream
     fputs	   puts.3s	put a string on a stream
     fread	   fread.3s	buffered binary input/output
     freopen	   fopen.3s	open a stream
     fscanf	   scanf.3s	formatted input conversion
     fseek	   fseek.3s	reposition a stream
     ftell	   fseek.3s	reposition a stream
     fwrite	   fread.3s	buffered binary input/output
     getc	   getc.3s	get character or word from stream
     getchar	   getc.3s	get character or word from stream
     gets	   gets.3s	get a string from a stream
     getw	   getc.3s	get character or word from stream
     printf	   printf.3s	formatted output conversion
     putc	   putc.3s	put character or word on a stream
     putchar	   putc.3s	put character or word on a stream
     puts	   puts.3s	put a string on a stream
     putw	   putc.3s	put character or word on a stream


Printed 11/26/99	  May 13, 1986				2


STDIO(3S)	    UNIX Programmer's Manual		STDIO(3S)


     rewind	   fseek.3s	reposition a stream
     scanf	   scanf.3s	formatted input conversion
     setbuf	   setbuf.3s	assign buffering to a stream
     setbuffer	   setbuf.3s	assign buffering to a stream
     setlinebuf    setbuf.3s	assign buffering to a stream
     sprintf	   printf.3s	formatted output conversion
     sscanf	   scanf.3s	formatted input conversion
     ungetc	   ungetc.3s	push character back into input stream


Printed 11/26/99	  May 13, 1986				3