Thank you for the input. Using sigsetjmp et al. solved the problem. These functions were not available in V7 Unix when rz/sz was first written. -- Chuck Forsberg caf@xxxxxxxx www.omen.com 503-614-0430 Developer of Industrial ZMODEM(Tm) for Embedded Applications Omen Technology Inc "The High Reliability Software" 10255 NW Old Cornelius Pass Portland OR 97231 FAX 629-0665