GETC(3S) (C Programming Language Utilities) GETC(3S)
NAME
getc, getchar, fgetc, getw - get character or word from a
stream
SYNOPSIS
#include <stdio.h>
int getc (stream)
FILE *stream;
int getchar ()
int fgetc (stream)
FILE *stream;
int getw (stream)
FILE *stream;
DESCRIPTION
getc returns the next character (i.e., byte) from the named
input stream, as an integer. It also moves the file
pointer, if defined, ahead one character in stream. getchar
is defined as getc(stdin). getc and getchar are macros.
Fgetc behaves like getc, but is a function rather than a
macro. Fgetc runs more slowly than getc, but it takes less
space per invocation and its name can be passed as an
argument to a function.
Getw returns the next word (i.e., integer) from the named
input stream. Getw increments the associated file pointer,
if defined, to point to the next word. The size of a word
is the size of an integer and varies from machine to
machine. Getw assumes no special alignment in the file.
SEE ALSO
fclose(3S), ferror(3S), fopen(3S), fread(3S), gets(3S),
putc(3S), scanf(3S), stdio(3S).
DIAGNOSTICS
Page 1 May 1989
GETC(3S) (C Programming Language Utilities) GETC(3S)
These functions return the constant EOF at end-of-file or
upon an error. Because EOF is a valid integer, ferror(3S)
should be used to detect getw errors.
WARNING
If the integer value returned by getc, getchar, or fgetc is
stored into a character variable and then compared against
the integer constant EOF, the comparison may never succeed,
because sign-extension of a character on widening to integer
is machine-dependent.
CAVEATS
Because it is implemented as a macro, getc evaluates a
stream argument more than once. In particular, getc(*f++)
does not work sensibly. Fgetc should be used instead.
Because of possible differences in word length and byte
ordering, files written using putw are machine-dependent,
and may not be read using getw on a different processor.
Page 2 May 1989