#include <phigs.h>			/* get HP-PHIGS definitions for C */#include <stdio.h>			/* get standard I/O definitions */main()					/* file "Error.c" */{    Pint	WorkstnID = 1;		/* workstation identifier */    Pint	ConnID;			/* connection identifier */    Pint	WorkstnType = POIDDX;	/* out/in, direct, dbl bfr, Xwindow */    static Plimit BadLimits =		/* deliberately illegal values */		{0.0, 0.0, 0.0, 0.0};    Pint	ErrorRtn;		/* returned from "pescape_u700" */        void	MyErrorHandler();	/* forward reference */    void	(*OldHandler)();	/* pointer for previous handler */    popen_phigs((char *) stderr, 0);	/* errors go to "stderr" */    pescape_u4("/dev/screen/phigs_window", &ConnID);    popen_ws(WorkstnID, (void *) ConnID, WorkstnType);    /*--- make an error with the default error-handler in effect -----------*/    printf("--- Default error-handler in effect -------------------------\n");    pset_ws_win(WorkstnID, &BadLimits);    /*--- turn off error handling completely -------------------------------*/    printf("--- No error-handler in effect ------------------------------\n");    pset_err_hand_mode(PERR_OFF);    pset_ws_win(WorkstnID, &BadLimits);    /*--- install custom error-handler and make error again ----------------*/    printf("--- Custom error-handler in effect --------------------------\n");    pset_err_hand_mode(PERR_ON);    pset_err_hand(MyErrorHandler, &OldHandler);	/* replace handler */    pset_ws_win(WorkstnID, &BadLimits);    pclose_ws(WorkstnID);    pclose_phigs();}/****************************************************************************/void MyErrorHandler(ErrorNo, FuncID, ErrorFile)int	*ErrorNo;			/* which error happened? */ int	*FuncID;			/* which routine had the error? */void	*ErrorFile;			/* print error messages where? */{    printf("MyErrorHandler: Error %d occurred in routine %d.\n", *ErrorNo,      *FuncID);    printf("My own call to the ERROR LOGGING routine (perr_log):\n");    perr_log(*ErrorNo, *FuncID, ErrorFile);}