From: Soyka <mgs AT ssd DOT ray DOT com>
Date: Thu, 27 Apr 1995 09:42:01 -0400
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: djgpp.env

I am having a problem changing the default graphics driver
using the djgpp.env environment file.  The default driver does NOT
work with my mach32 graphics adapter- when trying to run the
t05 test program, I get a
   "Graphics initialization error -- probably incorrect driver"
message, the program hangs and a control-break is needed to get
to the DOS prompt.

After reading the docs, I found out I could change the default driver
via the GO32 environment variable.  So I tried a number of the other 
drivers in the drivers subdirectory and found that
   set go32=c:/djgpp/drivers/atipro.grd topline
allowed t05 to run without error (topline was added for reasons
that will be apparent later).

Wishing to make this a permanent selection, I added the line
   GO32=driver %DJGPP%/drivers/atipro.grd topline
to my djgpp.env file and cleared the variable from the environment.
Rerunning t05.bat, I saw the topline messages during the build but
once again the "Graphics initialization error ..." message appeared
when I t05 ran.  

I then inserted a call to getkey() as the first executable
statement in t05.c and reran t05.bat.  When getkey is reached,
I don't see the expected status info on the top line and still get
the graphics error when GrLine() is called. 

Suspecting that something might be "funny" with GO32 entry in
djgpp.env, I moved the GO32 line into a .BAT file, defined DJGDIR,
and executed the bat file and t05, and everything works OK.
Interestingly, with the GO32 environment variable defined and also
present in djgpp.env, everything is OK, even though GO32 is not
prefixed with '+'.  

In summary, so long as the environment variable GO32 is defined
before go32 is invoked, everything is OK but if I delete the
environment variable, things break.  

As a work around, I've put the set GO32 statement into my setupdjg.bat
file. I guess I should be satisfied and move on but something's
not right here.  Anybody have any ideas what the problem is or how
I can obtain additional diagnostics?


Copy of djgpp.env follows:
>>  DJDIR=%:/>DJGPP%
>>  
>>  +USER=dosuser
>>  +TMPDIR=%DJDIR%/tmp
>>  +GO32TMP=%DJDIR%/tmp
>>  GO32=driver c:/gcc/drivers/atipro.grd gw 640 gh 480 topline
>>  
>>  [bison]
>>  BISON_HAIRY=%DJDIR%/lib/bison.hairy
>>  BISON_SIMPLE=%DJDIR%/lib/bison.simple
>>  
>>  [cpp]
>>  CPLUS_INCLUDE_PATH=%/>;CPLUS_INCLUDE_PATH%%DJDIR%/cplusinc;%DJDIR%/include
>>  C_INCLUDE_PATH=%/>;C_INCLUDE_PATH%%DJDIR%/include
>>  OBJCPLUS_INCLUDE_PATH=%/>;OBJCPLUS_INCLUDE_PATH%%DJDIR%/include;%DJDIR%/include/objc
>>  OBJC_INCLUDE_PATH=%/>;OBJC_INCLUDE_PATH%%DJDIR%/include;%DJDIR%/include/objc
>>  
>>  [flex]
>>  FLEX_SKELETON=%DJDIR%/lib/flex.skeleton
>>  
>>  [gcc]
>>  COMPILER_PATH=%/>;COMPILER_PATH%%DJDIR%/bin
>>  LIBRARY_PATH=%/>;LIBRARY_PATH%%DJDIR%/lib
>>  
>>  [info]
>>  INFOPATH=%/>;INFOPATH%%DJDIR%/docs;%DJDIR%/docs/djgpp;%DJDIR%/docs/texinfo

Copy of modified t05.c follows:
>>  #include <stdlib.h>
>>  #include <graphics.h>
>>  
>>  #define MODS
>>  
>>  main()
>>  {
>>    int c, i, mx, my;
>>    char buf[100];
>>  
>>  #if defined(MODS)
>>    {
>>      char * penv;
>>  
>>      penv = getenv("GO32");
>>      if (penv != 0 )   printf("%s = %s\n","GO32",penv);
>>  
>>      getkey();
>>    }
>>  #endif
>>  
>>    GrSetMode(GR_default_graphics);
>>    c = GrAllocColor(255, 255, 0);
>>    mx = GrSizeX()-1;
>>    my = GrSizeY()-1;
>>    GrLine( 0, 0,  mx,  0, c);
>>    GrLine(mx, 0,  mx, my, c);
>>    GrLine(mx, my,  0, my, c);
>>    GrLine( 0, my,  0,  0, c);
>>    mx = GrSizeX()/2;
>>    my = GrSizeY()/2;
>>    GrLine( 0, 0,  mx, my, c);
>>    sprintf(buf, "(%d,%d)", mx, my);
>>    GrTextXY(mx, my, buf, GrWhite(), GrBlack());
>>    getkey();
>>    GrSetMode(GR_default_text);
>>  }