How to Shell Out to System Prompt from Within a C Program

MS-DOS                 | OS/2       | WINDOWS

The information in this article applies to:

• The C Run-time (CRT) included with:

      - Microsoft C for MS-DOS, versions 6.0, 6.0a, and 6.0ax
      - Microsoft C for OS/2, versions 6.0, and 6.0a
      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, and
        1.52
  

SUMMARY

In Microsoft C, the spawnlp() function may be used to shell out to the MS- DOS or OS/2 command prompt from within a C program by spawning a copy of the MS-DOS or OS/2 command interpreter. This method is demonstrated in the sample program below. The P_WAIT mode must be used under MS-DOS and is recommended under OS/2 as well.

MORE INFORMATION

The spawnl() function may also be used if a path to the command interpreter is given explicitly in argument 1 of the parameter list. See the documentation or online help supplied with your version of the compiler for more information about the spawn family of functions.

Sample Code

/* Compile options needed: none
*/

#include <process.h>
#include <stdio.h>
#include <stdlib.h>

void main(void)

   if ( _osmode == DOS_MODE )   /* Running under MS-DOS */
      {
       printf("Shelling out to DOS, type 'EXIT' to return\n");
       spawnlp(P_WAIT, "COMMAND.COM", "COMMAND.COM", NULL);
      }
   else   /* Running under OS/2 */
      {
       printf("Shelling out to OS/2, type 'EXIT' to return\n");
       spawnlp(P_WAIT, "CMD.EXE", "CMD.EXE", NULL);
      }
   printf("Back from Shell\n");

NOTE: For more information on spawning applications in Win32 operating systems, refer to Knowledge Base article Q125213.