stdio - standard buffered input/output package


#include <stdio_p.h>

FILE *stdin, *stdiout, *stderr;


Some functions described in this manual constitue an efficient, user-level I/O buffering scheme. The in-line macros, getc(3P) and putc(3P) handle characters quickly. The macros getchar, putchar, and the higher-level routines fgetc, fgets, fprintf, fputc, fputs, fread, fscanf, fwrite, gets, getw, printf, puts, putw, and scanf 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(3P) creates certain descriptive data for a stream and returns a pointer to designate the stream in all furthur transactions. Normally, there are 3 open streams with constant pointers declared in the include file and associated with the standard open files:

standard input file

standard output file

standard error file.

A constant "pointer" NULL (0) designates the null stream.

An integer constant EOF (-1) is returned upon end-of-file or error by most integer functions that deal with streams (see the individual descriptions for details).

Any program that uses this package must inculde the header file of pertinent macro definitions, as follows:

#include <stdio_p.h>
The functions and constants mentioned in the entries of this manual are declared in that include file and need no further declaration. The constants and the folowing functions are implemented as macros (redeclaration of these names is perilous): getc, getchar, putc, putchar, feof, ferror, and fileno.


open(2P) , close(2P) , read(2P) , write(2P) , fclose(3P) , ferror(3P) , fread(3P) , fseek(3P) , getc(3P) , printf(3P) , putc(3P) , scanf(3P) , setbuf(3P).


Invalid stream pointers will usually cause grave disorder, possibly including program termination. Individual function descriptions describe the possible error conditions.