plan9port/man/man3/readcons.3

.TH READCONS 3
.SH NAME
readcons \- prompt console for input
.SH SYNOPSIS
.B
#include <u.h>
.PP
.B
#include <libc.h>
.PP
.B
char *readcons(char *prompt, char *def, int secret)
.SH DESCRIPTION
.I Readcons
prompts at the console for input.
It returns a NUL-terminated buffer containing the input
without a final newline.
The buffer should be freed (and perhaps cleared first) 
when no longer needed.
.PP
If the user types an empty string (just a newline) and
.I def
is non-zero, then a copy of 
.I def
is returned instead of the empty string.
.PP
If
.I secret
is non-zero, the input is not echoed to the screen.
.SH EXAMPLE
A stripped-down version of
.I netkey
(see
.IR passwd (1)):
.IP
.EX
pass = readcons("password", nil, 1);
passtokey(key, pass);
memset(pass, 0, strlen(pass));
free(pass);
for(;;){
	chal = readcons("challenge", nil, 0);
	sprint(buf, "%d", strtol(chal, 0, 10));
	free(chal);
	netcrypt(key, buf);
	print("response: %s\n", buf);
}
.EE
.SH SOURCE
.B \*9/src/lib9/readcons.c