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researchv10 Dan Cross

.ds ZZ DEVELOPMENT PACKAGE
.TH SENDCHAR 3R "630 MTG"
.XE "sendchar()"
.XE "sendnchars()"
.SH NAME
sendchar, sendnchars \- send character(s) to host
.SH SYNOPSIS
\f3
int sendchar (c)
.br
char c;
.sp
void sendnchars (n, p)
.br
int n;
.br
char \(**p;
\fR
.SH DESCRIPTION
The
.I sendchar
function
sends a single byte to the host
which will normally be read on the standard input of the host process.
The bytes sent will be processed as though they were typed on the
keyboard by the user.
.PP
Since local programs have no host connection, a call to
.I sendchar
by a local program will always return -1.
Sendchar will always return 1 for non-local programs.
.PP
The
.I sendnchars
function is similar to 
.I sendchar
except
.I n
characters pointed to by
.I p
are sent to the host.
.PP
A call to
.I sendchar
or 
.I sendnchars
by an application program causes the bytes to be sent to the host computer to
be placed into a buffer in the terminal. The terminal will then send the bytes
in the buffer to the host as fast
as the communication line to the host is able to transmit.
An application program is generally able to queue requests to
send bytes to the host much faster than the terminal is able
to actually send the bytes over the communication line to the host.
So, if an application rapidly sends many bytes to the host,
internal terminal buffers eventually fill up. When this happens,
the
.I sendchar
and
.I sendnchars
routines will call
.I wait
to block the calling process until internal buffers are no longer full.
This whole process is transparent to applications, but application program
writers may want to be aware that a call to
.I sendchar
or 
.I sendnchars
may not return immediately.
.SH EXAMPLE
The following program will send a
.I ls
command to the host and display its output.
Typing a 'q' on the keyboard will cause the program to exit.
.PP
.RS 3
.nf
.ft CM
#include <dmd.h>

main()
{
	int c;

	request(SEND|RCV|KBD);
	sendnchars(3, "ls\er");
	do {
		wait(RCV|KBD);
		while( (c=rcvchar()) != -1 )
			lputchar(c);
	} while(kbdchar() != 'q');
}
\fR
.fi
.RE
.SH SEE ALSO
local(3R), rcvchar(3R), resources(3R).

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