/*	pops_device.c:  Thu Oct 10 15:50:36 EDT 2002

	Demonstrates "Pop's Device", named by Tak-Shing Chan 
	in comp.lang.c on 10/1/02 in response to Dan Pop's
	suggestion for using an esoteric capability
	of scanf() to properly limit input buffers.  Proposed
	as an alternative to fgets().

	Specifically, the idiom is stated as:

	1.	char buffer[NUMBER+1]="";
	2.	int rc=scanf("%NUMBER[^\n]%*[^\n]",buffer);
	3.	if(rc>=0) getchar();

	NUMBER is the buffer length desired.
	Line 2 grabs up to NUMBER chars, until newline.
	Line 3 eats up the newline that scanf() leaves behind.  rc == 0
	if <RETURN> was only key pressed, i.e. no input.  rc ==1 for
	input was available.  rc < 0 if some abort signal (e.g. ^D) 
	terminated the input.
*/

#include <stdio.h>
#include <stdlib.h>

int main(void)
{
	char buffer[80+1]="";
	int rc;

	printf("Testing `Pop's Device'\n\n");
	printf("Enter a string: ");
	fflush(stdout);
	rc=scanf("%80[^\n]%*[^\n]",buffer);
	printf("RC=%d\n",rc);		/* checkpoint debug */
	if(rc>=0) {
		int c;			/* checkpoint debug */
		c=getchar();
		printf("%02X\n",c);	/* checkpoint debug */
		printf("buffer: %s\n",buffer);
	}
	return EXIT_SUCCESS;
}