DosQueryProcessInfo will return information about processes and tasks running in the system.

#define INCL_WPOS
#include <os2.h>

ULONG     InfoType;
ULONG     ID;
ULONG     InfoLevel;
PVOID     InfoBuffer;
PULONG    InfoBufferLength;
PULONG    InfoEntryCount;
APIRET    ulrc;              /*  Return code. */

ulrc = DosQueryProcessInfo(InfoType, ID, InfoLevel,
         InfoBuffer, InfoBufferLength, InfoEntryCount);