GETC
Section: POSIX Programmer's Manual (3P)
Updated: 2003
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PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
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 constant 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, Copyright (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.opengroup.org/unix/online.html .