gmem cannot be used for midisend_buf...?

[Fabian]

Playing around with MIDI stuff, it seems that gmem does not behave as an ordinary buffer when it comes to midisend_buf.

I can do this just fine:

@init
searchDeviceRequest = "\xF0\x42\x50\x00\x44\xF7"; // Minilogue stuff
buf = 1000;
offset = 0;
loop(strlen(searchDeviceRequest),
	buf[offset+4] = str_getchar(searchDeviceRequest, offset);
	offset += 1;
);

@block
midisend_buf(0, buf+4, strlen(searchDeviceRequest));

And I do get the expected result; the correct sysex is sent out and the Minilogue replies with the expected message.

However, if I use gmem as buffer instead:

options:gmem=MF_TestSysExMsg

@init
searchDeviceRequest = "\xF0\x42\x50\x00\x44\xF7"; // Minilogue stuff
offset = 0;
loop(strlen(searchDeviceRequest),
	gmem[offset+4] = str_getchar(searchDeviceRequest, offset);
	offset += 1;
);

@block
midisend_buf(0, gmem+4, strlen(searchDeviceRequest));

this sends the string F0 00 00 00 00 00 00 F7, which (not unexpectedly) the Minilogue does not reply to at all.

Does anyone know what's up with this?

[Tale]

It would seem that you can use gmem[] only with square brackets, but not as a "pointer", i.e. gmem[i] = x is OK, but (gmem+i)[0] = x doesn't work as expected. That is, the latter uses a variable that happens to be named gmem, so it accesses local memory at addres gmem+i, but it doesn't access global memory. And I guess the same goes for midisend_buf(), and basically anywhere where you use a pointer.

[Fabian]

Originally Posted by Tale

It would seem that you can use gmem[] only with square brackets, but not as a "pointer", i.e. gmem[i] = x is OK, but (gmem+i)[0] = x doesn't work as expected. That is, the latter uses a variable that happens to be named gmem, so it accesses local memory at addres gmem+i, but it doesn't access global memory. And I guess the same goes for midisend_buf(), and basically anywhere where you use a pointer.

Aha. Yeah I guess that would explain the behavior I see.

So I would have to copy the elements from gmem into a local buffer to use for midisend_buf. It is a pity, but would work.

Thanks