NAME
fgetc, getc,
getchar, getc_unlocked,
getchar_unlocked, getw
— get next character or word
from input stream
LIBRARY
library “libc”
SYNOPSIS
#include
<stdio.h>
int
fgetc(FILE
*stream);
int
getc(FILE
*stream);
int
getchar();
int
getc_unlocked(FILE
*stream);
int
getchar_unlocked();
int
getw(FILE
*stream);
DESCRIPTION
Thefgetc()
function obtains the next input character (if present) from the stream pointed
at by stream, or the next character pushed back on the
stream via ungetc(3).
The
getc()
function acts essentially identically to fgetc(),
but is a macro that expands in-line.
The
getchar()
function is equivalent to: getc with the argument stdin.
The
getc_unlocked()
and
getchar_unlocked()
functions provide functionality identical to that of
getc() and getchar(),
respectively, but do not perform implicit locking of the streams they
operate on. In multi-threaded programs they may be used
only
within a scope in which the stream has been successfully locked by the
calling thread using either
flockfile(3) or
ftrylockfile(3), and may later be released using
funlockfile(3).
The
getw()
function obtains the next int (if present) from the stream
pointed at by stream.
RETURN VALUES
If successful, these routines return the next requested object
from the stream. If the stream is at end-of-file or a
read error occurs, the routines return EOF. The
routines feof(3) and
ferror(3) must be used to distinguish between end-of-file and error.
If an error occurs, the global variable errno is set
to indicate the error. The end-of-file condition is remembered, even on a
terminal, and all subsequent attempts to read will return
EOF until the condition is cleared with
clearerr(3).
SEE ALSO
ferror(3), flockfile(3), fopen(3), fread(3), ftrylockfile(3), funlockfile(3), putc(3), ungetc(3)
STANDARDS
The fgetc(),
getc() and getchar()
functions conform to ANSI X3.159-1989
(“ANSI C89”). The
getc_unlocked() and
getchar_unlocked() functions conform to
ISO/IEC 9945-1:1996 (“POSIX.1”).
HISTORY
The getc() and
getw() functions appeared in
Version 1 AT&T UNIX.
BUGS
Since EOF is a valid integer value,
feof(3) and
ferror(3) must be used to check for failure after calling
getw(). The size and byte order of an
int varies from one machine to another, and
getw() is not recommended for portable
applications.