GETC(3P)                                            POSIX Programmer's Manual                                           GETC(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       getc - get a byte from a stream

SYNOPSIS
       #include <stdio.h>

       int getc(FILE *stream);


DESCRIPTION
       The  getc()  function  shall be equivalent to fgetc(), except that if it is implemented as a macro it may evaluate stream
       more than once, so the argument should never be an expression with side effects.

RETURN VALUE
       Refer to fgetc().

ERRORS
       Refer to fgetc().

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       If the integer value returned by getc() is stored into a variable of type char and then compared against the integer con-
       stant  EOF, the comparison may never succeed, because sign-extension of a variable of type char on widening to integer is
       implementation-defined.

       Since it may be implemented as a macro, getc() may treat incorrectly a stream argument with side effects. In  particular,
       getc(*f++) does not necessarily work as expected.  Therefore, use of this function should be preceded by "#undef getc" in
       such situations; fgetc() could also be used.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       fgetc(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                      GETC(3P)