/* Functions resident in an overlay can call back functions resident in the
* main program at any time without any precautions. The function show() is
* an example for such a function resident in the main program.
*/
void show(char *name)
{
char line1[40];
sprintf(line1, CBOLDON "Overlay Demo - Overlay %s" CPLAINTEXT, name);
DlgBoxOk(line1, "Click OK to return to Main.");
}
void _afailed (char* file, unsigned line)
{
ExitTurbo();
drawWindow.top = 0;
drawWindow.left = 0;
drawWindow.bot = 15;
drawWindow.right = 150;
dispBufferOn = ST_WR_FORE|ST_WR_BACK;
SetPattern(0);
Rectangle();
FrameRectangle(0xff);
PutString(CBOLDON "file: ", 10, 10);
PutString(file, 10, r11);
PutString(CBOLDON " line: ", 10, r11);
PutDecimal(0, line, 10, r11);
DlgBoxOk(CBOLDON "ASSERTION FAILED", "PROGRAM TERMINATED" CPLAINTEXT);
exit (2);
}
void main(int /*argc*/, char *argv[])
{
if (OpenRecordFile(argv[0])) {
_poserror("OpenRecordFile");
return;
}
DlgBoxOk(CBOLDON "Overlay Demo - Main" CPLAINTEXT,
"Click OK to call Overlay One.");
if (PointRecord(1)) {
_poserror("PointRecord.1");
return;
}
/* The macro definitions OVERLAY_ADDR and OVERLAY_SIZE were generated in
* overlay-demores.h by grc65. They contain the overlay area address and
* size specific to a certain program.
*/
if (ReadRecord(OVERLAY_ADDR, OVERLAY_SIZE)) {
_poserror("ReadRecord.1");
return;
}
/* The linker makes sure that the call to foo() ends up at the right mem
* addr. However it's up to user to make sure that the - right - overlay
* is actually loaded before making the the call.
*/
foo();
DlgBoxOk(CBOLDON "Overlay Demo - Main" CPLAINTEXT,
"Click OK to call Overlay Two.");
if (PointRecord(2)) {
_poserror("PointRecord.2");
return;
}
/* Replacing one overlay with another one can only happen from the main
* program. This implies that an overlay can never load another overlay.
*/
if (ReadRecord(OVERLAY_ADDR, OVERLAY_SIZE)) {
_poserror("ReadRecord.2");
return;
}
bar();
DlgBoxOk(CBOLDON "Overlay Demo - Main" CPLAINTEXT,
"Click OK to call Overlay Three.");
if (PointRecord(3)) {
_poserror("PointRecord.3");
return;
}
if (ReadRecord(OVERLAY_ADDR, OVERLAY_SIZE)) {
_poserror("ReadRecord.3");
return;
}
foobar();
if (CloseRecordFile()) {
_poserror("CloseRecordFile");
return;
}
}