getc(3)

NAME

fgetc, getc, getchar, getc_unlocked, getchar_unlocked, getw — get next character or word from input stream

SYNOPSIS

#include <stdio.h>

int
fgetc(FILE *stream);

int
getc(FILE *stream);

int
getchar(void);

int
getc_unlocked(FILE *stream);

int
getchar_unlocked(void);

int
getw(FILE *stream);

DESCRIPTION

The fgetc() 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 perform the same action, but do not obtain the stream lock. They require that the stream first be locked with flockfile(3) for thread safe operation.

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), getwc(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 IEEE Std 1003.1-2024 (“POSIX.1”).

HISTORY

The getc() and getw() functions first appeared in Version 1 AT&T UNIX; getchar() in Version 2 AT&T UNIX; and fgetc() in Version 7 AT&T UNIX. The getc_unlocked() and getchar_unlocked() functions have been available since OpenBSD 2.5.

BUGS

Since EOF is a valid integer value, feof(3) and ferror(3) must be used to check for failure after calling getw().

Since the size and byte order of an int may vary from one machine to another, getw() is not recommended for portable applications.