stdio(3S)                                               stdio(3S)



     NAME
          stdio - standard buffered input/output package

     SYNOPSIS
          #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 input/output function may be grouped
          into the following categories:  file access, file status,
          input, output, miscellaneous.  For lists of the functions in
          each category, refer to the ``Libraries'' sections of Oreo
          Programming Languages and Tools, Volume 1.  The in-line
          macros getc(3S) and putc(3S) handle characters quickly.  The
          macros getchar and 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).

          An integer constant BUFSIZ specifies the size of the buffers
          used by the particular implementation.

          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: getc,



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     stdio(3S)                                               stdio(3S)



          getchar, putc, putchar, feof, ferror, clearerr, and fileno.
          Redeclaration of these names is perilous.

          The <stdio.h> file is illustrated in the  ``Libraries''
          sections of the Oreo Programming Languages and Tools, Volume
          1.

     SEE ALSO
          open(2), close(2), lseek(2), pipe(2), read(2), ctermid(3S),
          cuserid(3S), fclose(3S), ferror(3S), fopen(3S), fread(3S),
          fseek(3S), getc(3S), gets(3S), popen(3S), printf(3S),
          putc(3S), puts(3S), scanf(3S), setbuf(3S), system(3S),
          tmpfile(3S), tmpnam(3S), ungetc(3S), write(3).

     DIAGNOSTICS
          Invalid stream pointers cause serious errors, possibly
          including program termination.  Individual function
          descriptions describe the possible error conditions.





































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