getc, fgetc, getchar, getw

Purpose

     Gets a character or word from an input stream.

Library

     Standard I/O Library (libc.a)

Syntax

     #include <stdio.h>

     int getc (stream)                         int getchar ( )
     FILE *stream;
                                               int getw (stream)
     int fgetc (stream)                        FILE *stream;
     FILE *stream;
     Description

     The getc macro returns the next character (byte) from the
     input  specified by  the stream  parameter and  moves the
     file pointer, if defined,  ahead one character in stream.
     getc is a macro and cannot  be used where a subroutine is
     necessary; for example, a subroutine pointer cannot point
     to it.

     Because it is implemented as  a macro, getc does not work
     correctly with a stream  parameter that has side effects.
     In particular, the following does not work:

       getc(*f++)

     In cases like this, use the fgetc subroutine instead.

     The fgetc subroutine performs  the same function as getc,
     but  fgetc is  a genuine  subroutine, not  a macro.   The
     fgetc subroutine  runs more  slowly than getc,  but takes
     less space.

     The  getchar macro  returns the  next character  from the
     standard input stream, stdin.   Note that getchar is also
     a macro.

     The getw subroutine returns the  next word (int) from the
     input specified  by the  stream parameter  and increments
     the associated file pointer, if  defined, to point to the
     next word.   The size of  a word varies from  one machine
     architecture to another.  The getw subroutine returns the
     constant  EOF at  end-of-file  or when  an error  occurs.
     Since  EOF is  a  valid integer  value,  feof and  ferror
     should be  used to check  the success of getw.   The getw
     subroutine assumes no special alignment in the file.

     Because of  possible differences in word  length and byte
     ordering from one machine  architecture to another, files
     written using  putw are machine-dependent and  may not be
     readable using getw on a different type of processor.

     Return Value

     These subroutines and macros  return the integer constant
     EOF at end-of-file or upon an error.

     Related Information

     In this book:  "feof,  ferror, clearerr, fileno," "fopen,
     freopen,   fdopen,"  "fread,   fwrite,"  "gets,   fgets,"
     "NLgetctab,"  "putc,   putchar,  fputc,   putw,"  "scanf,
     fscanf,   sscanf,  NLscanf,   NLfscanf,  NLsscanf,"   and
     "standard i/o library."