This example starts a windowed OS/2 session.

#define INCL_DOSSESMGR
#define INCL_DOSERRORS
#include <stdio.h>
#include <os2.h>

int main(VOID) {
   STARTDATA SData       = {0};
   PSZ       PgmTitle    = "Test Program", /* Title of new session     */
             PgmName     = "CMD.EXE";  /* This starts an OS/2 session  */
   APIRET    rc          = NO_ERROR;   /* Return code                  */
   PID       pid         = 0;          /* PID returned                 */
   ULONG     ulSessID    = 0;          /* Session ID returned          */
   UCHAR     achObjBuf[256] = {0};     /* Error data if DosStart fails */

   SData.Length  = sizeof(STARTDATA);
   SData.Related = SSF_RELATED_INDEPENDENT; /* start an independent session */
   SData.FgBg    = SSF_FGBG_FORE;           /* start session in foreground  */
   SData.TraceOpt = SSF_TRACEOPT_NONE;      /* No trace                     */
             /* Start an OS/2 session using "CMD.EXE /K" */
   SData.PgmTitle = PgmTitle;
   SData.PgmName = PgmName;
   SData.PgmInputs = "/K";                     /* Keep session up           */

   SData.TermQ = 0;                            /* No termination queue      */
   SData.Environment = 0;                      /* No environment string     */
   SData.InheritOpt = SSF_INHERTOPT_SHELL;     /* Inherit shell's environ.  */
   SData.SessionType = SSF_TYPE_WINDOWABLEVIO; /* Windowed VIO session      */
   SData.IconFile = 0;                         /* No icon association       */
   SData.PgmHandle = 0;
           /* Open the session VISIBLE and MAXIMIZED */
   SData.PgmControl = SSF_CONTROL_VISIBLE | SSF_CONTROL_MAXIMIZE;
   SData.InitXPos  = 30;     /* Initial window coordinates              */
   SData.InitYPos  = 40;
   SData.InitXSize = 200;    /* Initial window size */
   SData.InitYSize = 140;
   SData.Reserved = 0;
   SData.ObjectBuffer  = achObjBuf; /* Contains info if DosExecPgm fails */
   SData.ObjectBuffLen = (ULONG) sizeof(achObjBuf);

   rc = DosStartSession(&SData, &ulSessID, &pid);  /* Start the session */

   if (rc != NO_ERROR) {
      printf ("DosStartSession error : return code = %u\n", rc);
      return 1;
   }
   return NO_ERROR;
}