Date: 18 Jun 1995 02:05:15 -0500 (CDT)
From: jmccawle AT cs DOT uno DOT edu (Cap'n Hardgeus)
Subject: CD-ROM in DJGPP
To: djgpp AT sun DOT soe DOT clarkson DOT edu

     I downloaded a file called cdrom_c.zip which is a library of routines
for playing cdrom music using MSCDEX.  I am trying to port them over to 
DJGPP and have not been too successful.  I am using _go32_dpmi_simulate_int for
the int 0x2f interrupt, and so all of the buffers I send have to be in 
conventional memory.  I am using _go32_dpmi_allocate_dos_memory and copying
the buffers to and from this space.  Based on code I have seen it seems like
I'm doing this correctly.  However, one of the feilds of the buffer is a 
pointer to ANOTHER buffer (yuck!) and so I allocate another dos buffer.
I assume that I should take the segment and the offset and make a far pointer
out of it for the interrupt to use: (seg << 16) | offset.  I am having a lot 
of trouble debugging because I can't use that far pointer to see what it is
pointing to.

     Anyone have any tips they could give me on this type of thing?  This is 
a pretty specific problem, but any code slightly related to it would make me
very happy!  I want to know exactly what this interrupt expects, but I haven't
found any helpful documentation.

     John R. McCawley III
     Cap'n Hardgeus