#include	"calld.h"static FILE	*fpsys = NULL;static int	 syslineno;			/* for error messages */static char	 sysline[MAXLINE];		/* can't be automatic; sys_next() returns pointers into here *//* * Read and break apart a line in the Systems file. */long						/* return >0 if OK, -1 on EOF */sys_next(Systems *sysptr)	/* structure is filled in with pointers */{	if (fpsys == NULL) {		if ((fpsys = fopen(SYSTEMS, "r")) == NULL)			log_sys("can't open %s", SYSTEMS);		syslineno = 0;	}again:	if (fgets(sysline, MAXLINE, fpsys) == NULL)		return(-1);		/* EOF */	syslineno++;	if ((sysptr->name = strtok(sysline, WHITE)) == NULL) {		if (sysline[0] == '\n')			goto again;		/* ignore empty line */		log_quit("missing `name' in Systems file, line %d", syslineno);	}	if (sysptr->name[0] == '#')		goto again;			/* ignore comment line */	if ((sysptr->time = strtok(NULL, WHITE)) == NULL)		log_quit("missing `time' in Systems file, line %d", syslineno);	if ((sysptr->type = strtok(NULL, WHITE)) == NULL)		log_quit("missing `type' in Systems file, line %d", syslineno);	if ((sysptr->class = strtok(NULL, WHITE)) == NULL)		log_quit("missing `class' in Systems file, line %d", syslineno);	if ((sysptr->phone = strtok(NULL, WHITE)) == NULL)		log_quit("missing `phone' in Systems file, line %d", syslineno);	if ((sysptr->login = strtok(NULL, "\n")) == NULL)		log_quit("missing `login' in Systems file, line %d", syslineno);	return(ftell(fpsys));	/* return the position in Systems file */}voidsys_rew(void){	if (fpsys != NULL)		rewind(fpsys);	syslineno = 0;}voidsys_posn(long posn)		/* position Systems file */{	if (posn == 0)		sys_rew();	else if (fseek(fpsys, posn, SEEK_SET) != 0)		log_sys("fseek error");}