STDIO(3)						     Library Functions Manual							  STDIO(3)

NAME

       stdio - standard buffered input/output package

SYNOPSIS

       #include <stdio.h>

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

DESCRIPTION

       The  functions in the standard I/O library constitute a 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 the standard I/O manual pages are declared in the include file and need no further declaration.  The  con-
       stants,	and  the following `functions' are implemented as macros; redeclaration of these names is perilous: clearerr, getc, getchar, putc,
       putchar, feof, ferror, fileno.

SEE ALSO

       open(2), close(2), read(2), write(2), fclose(3), ferror(3), fopen(3), fread(3), fseek(3), getc(3), gets(3),  printf(3),	putc(3),  puts(3),
       scanf(3), setbuf(3), ungetc(3).

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.

       For purposes of efficiency, this implementation of the standard 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 necessary to fflush(3) 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 fork and abort.

LIST OF FUNCTIONS

       Name	   Appears on Page    Description
       clearerr      ferror(3)	  stream status inquiries
       fclose	     fclose(3)	  close or flush a stream
       fdopen	     fopen(3)	  open a stream
       feof	     ferror(3)	  stream status inquiries
       ferror	     ferror(3)	  stream status inquiries
       fflush	     fclose(3)	  close or flush a stream
       fgetc	     getc(3)	  get character or word from stream
       fgets	     gets(3)	  get a string from a stream
       fileno	     ferror(3)	  stream status inquiries
       fopen	     fopen(3)	  open a stream
       fprintf	     printf(3)	  formatted output conversion
       fputc	     putc(3)	  put character or word on a stream
       fputs	     puts(3)	  put a string on a stream
       fread	     fread(3)	  buffered binary input/output
       freopen	     fopen(3)	  open a stream
       fscanf	     scanf(3)	  formatted input conversion
       fseek	     fseek(3)	  reposition a stream
       ftell	     fseek(3)	  reposition a stream
       fwrite	     fread(3)	  buffered binary input/output
       getc	     getc(3)	  get character or word from stream
       getchar	     getc(3)	  get character or word from stream
       gets	     gets(3)	  get a string from a stream
       getw	     getc(3)	  get character or word from stream
       printf	     printf(3)	  formatted output conversion
       putc	     putc(3)	  put character or word on a stream
       putchar	     putc(3)	  put character or word on a stream
       puts	     puts(3)	  put a string on a stream
       putw	     putc(3)	  put character or word on a stream
       rewind	     fseek(3)	  reposition a stream
       scanf	     scanf(3)	  formatted input conversion
       setbuf	     setbuf(3)	  assign buffering to a stream
       setvbuf	     setbuf(3)	  assign buffering to a stream
       snprintf      printf(3)	  formatted output conversion
       sprintf	     printf(3)	  formatted output conversion
       sscanf	     scanf(3)	  formatted input conversion
       ungetc	     ungetc(3)	  push character back into input stream
       vfprintf      printf(3)	  formatted output conversion
       vfscanf	     scanf(3)	  formatted input conversion
       vprintf	     printf(3)	  formatted output conversion
       vscanf	     scanf(3)	  formatted input conversion
       vsnprintf     printf(3)	  formatted output conversion
       vsprintf      printf(3)	  formatted output conversion
       vsscanf	     scanf(3)	  formatted input conversion

4th Berkeley Distribution					   May 13, 1986 							  STDIO(3)