


      STDIO(3S)                   (UNIX 5.0)                  STDIO(3S)



      NAME
           stdio - standard buffered input/output package

      SYNTAX
           #include <stdio.h>

           FILE *stdin, *stdout, *stderr;

      DESCRIPTION
           The functions described in the entries of sub-class 3S of
           this manual constitute an efficient, user-level I/O
           buffering scheme.  The in-line macros getc(3S) and putc(3S)
           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(3S)
           creates certain descriptive data for a stream and returns 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 file and
           associated with the standard open files:

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

           A constant NULL (0) designates a nonexistent pointer.

           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 include the header
           file of pertinent macro definitions, as follows:

                #include <stdio.h>

           The functions and constants mentioned in the entries of
           sub-class 3S of this manual are declared in that header 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, clearerr, and fileno.

      SEE ALSO
           open(2), close(2), lseek(2), read(2), write(2), ctermid(3S),
           cuserid(3S), fclose(3S), ferror(3S), fopen(3S), fread(3S),
           fseek(3S), getc(3S), gets(3S), popen(3S), printf(3S),



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      STDIO(3S)                   (UNIX 5.0)                  STDIO(3S)



           putc(3S), puts(3S), scanf(3S), setbuf(3S), system(3S),
           tmpfile(3S), tmpnam(3S), ungetc(3S).

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
















































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