V4/usr/man/man3/getchr.3

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.th GETCHAR III 4/7/73
.sh NAME
getchar \*- read character
.sh SYNOPSIS
.ft B
getchar( )
.br
.ft R
.sh DESCRIPTION
.it Getchar
provides the simplest means of reading characters from
the standard input for C programs.
It returns successive characters until end-of-file,
when it returns ``\\0''.
.s3
Associated with this routine is an external variable
called \fIfin\fR, which is a structure containing
a buffer such as described under \fIgetc\fR (III).
.s3
Normally input via \fIgetchar\fR is unbuffered,
but if the file-descriptor (first) word of
.it fin
is non-zero,
.it getchar
calls
.it getc
with
.it fin
as
argument.
This means that
.s3
	fin = open(...)
.s3
makes
.it getchar
return (buffered) input from
the opened file; also
.s3
	fin = dup(0);
.s3
causes the standard input to be buffered.
.s3
Generally speaking,
.it getchar
should be used only for the simplest applications;
.it getc
is better when there are multiple input files.
.sh "SEE ALSO"
getc (III)
.sh DIAGNOSTICS
Null character returned on EOF or error.
.sh BUGS
\*-1 should be
returned on EOF; null is a legitimate character.