Microsoft KB Archive/116460

= BUG: Debugging With Mono And VGA Can Cause Screen Corruption =

PSS ID Number: 116460

Article Last Modified on 6/26/2001

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The information in this article applies to:


 * Microsoft CodeView for MS-DOS

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This article was previously published under Q116460



SYMPTOMS
When using the MS-DOS "mode mono" command to debug a graphics application on a secondary monochrome monitor (VGA being the primary monitor), screen corruption can result on both monitors.



RESOLUTION
To work around the problem, do not use the mode mono command. Instead, either debug on the primary VGA monitor or use the /2 command line option to display Codeview's windows on the monochrome monitor (instead of on the VGA monitor).



STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.



MORE INFORMATION
The sample program below demonstrates the problem. Build a debug version and enter the following commands at the DOS prompt:

msherc

mode mono

cv /b /s modes

Once you have started Codeview, enter the following commands in the command window:

bp .49

g

g

At this point both the VGA monitor and the monochrome monitor may display corrupt information.

Sample Code
/* Compiler Options Needed: /AL /Zi /Od


 * 1) include 
 * 2) include 
 * 3) include 

short modes[] = { _TEXTBW40,    _TEXTC40,      _TEXTBW80, _TEXTC80,     _MRES4COLOR,   _MRESNOCOLOR, _HRESBW,      _TEXTMONO,     _HERCMONO, _MRES16COLOR, _HRES16COLOR,  _ERESNOCOLOR, _ERESCOLOR,   _VRES2COLOR,   _VRES16COLOR, _MRES256COLOR, _ORESCOLOR }; char *names[] = { "TEXTBW40",   "TEXTC40",     "TEXTBW80", "TEXTC80",    "MRES4COLOR",  "MRESNOCOLOR", "HRESBW",     "TEXTMONO",    "HERCMONO", "MRES16COLOR", "HRES16COLOR", "ERESNOCOLOR", "ERESCOLOR",  "VRES2COLOR",  "VRES16COLOR", "MRES256COLOR","ORESCOLOR" }; short rows[] = { 60, 50, 43, 30, 25 }; /* Possible number of rows */

void main(void) { short c, i, j, x, y, row, num = sizeof(modes) / sizeof(modes[0]); struct _videoconfig vc; char b[500];             /* Buffer for string */

_displaycursor( _GCURSOROFF );

/* Try each mode. */ for( i = 0; i <= num; i++ ) { for (j = 0; j < 5; j++ ) {  /* Try each possible number of rows. */   row = _setvideomoderows( modes[i], rows[j] ); if( (!row) || (rows[j] != row) ) continue; else {   _getvideoconfig( &vc ); y = (vc.numtextrows - 12) / 2; x = (vc.numtextcols - 25) / 2;

/* Use text window to place output in middle of screen. */    _settextwindow( y, x, vc.numtextrows - y, vc.numtextcols - x );

/* Write all information to a string, then output string */ c = sprintf( b,     "Video mode: %s\n", names[i] ); c += sprintf( b + c, "X pixels:  %d\n", vc.numxpixels ); c += sprintf( b + c, "Y pixels:  %d\n", vc.numypixels ); c += sprintf( b + c, "Columns:   %d\n", vc.numtextcols ); c += sprintf( b + c, "Rows:      %d\n", vc.numtextrows ); c += sprintf( b + c, "Colors:    %d\n", vc.numcolors ); c += sprintf( b + c, "Bits/pixel: %d\n", vc.bitsperpixel ); c += sprintf( b + c, "Pages:     %d\n", vc.numvideopages ); c += sprintf( b + c, "Mode:      %d\n", vc.mode ); c += sprintf( b + c, "Adapter:   %d\n", vc.adapter ); c += sprintf( b + c, "Monitor:   %d\n", vc.monitor ); c += sprintf( b + c, "Memory:    %d",   vc.memory ); _outtext( b ); _getch; } } } _displaycursor( _GCURSORON ); _setvideomode( _DEFAULTMODE ); }

Additional query words: 4.00 4.01 4.10

Keywords: kb16bitonly KB116460

Technology: kbAudDeveloper kbCodeView kbZNotKeyword3

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