#
#include <cvl/cvl.h>
/*
 * IHEAD inputs a CVL picture header from the specified file descriptor.
 * The length of the comment field is returned, unless an error occurs,
 * in which case -1 is returned.
 * Joseph Pallas        9/18/80         cc -O -c ihead.c
 * Modified by Robert L. Kirby for more distinctive tag1 on Oct 8, 1980.
 */

int ihead (fdin, oldarea)
int fdin;
struct cvl_p *oldarea;
{
	register int numread;
	register int total;
	register char *p;

	p = (char *)oldarea;
	for(total = 0; total < sizeof *oldarea; total += numread)
	if((numread = read(fdin, &p[total], sizeof *oldarea - total)) == 0
	     || numread == -1)
		return(-1);
	if(oldarea->cv_tag != 'TCIP' + 020000000000)
		return(-1);
	return(oldarea->cv_lcom);
}