Microsoft KB Archive/36335
PRB: Unable to Call MSHERC.COM with a System Command PSS ID Number: Q36335 Article last modified on 06-11-1992 PSS database name: S_QuickC
1.01 2.00 2.50 2.51
SYMPTOMS A program that loads MSHERC.COM and then attempts to do graphics will fail. If you use spawn() or system() to run MSHERC.COM from within your program and then do a _setvideomode(_HERCMONO), _setvideomode() will state that you have an unsupported graphics mode.
CAUSE This behavior is expected. The graphics hardware is checked on initialization of the program. The Hercules graphic card is recognized only through MSHERC.COM, so when you start your program, the startup code has already checked for valid modes.
RESOLUTION Run MSHERC.COM from the MS-DOS prompt. When MSHERC is run from the MS-DOS command line prior to running the program, _setvideomode(_HERCMONO) will produce the correct results.
Although it is possible to run MSHERC.COM from within a program with spawn() or system(), it will not enable a graphics program to successfully set the video mode.
Additional reference words: 2.00 2.50 msherc
Copyright Microsoft Corporation 1992.