This function obtains the title under which a specified application is started, or is added to the Window List. (See also WinQuerySessionTitle, which you should use for preference.)

#define INCL_WINSWITCHLIST /* Or use INCL_WIN, INCL_PM, */
#include <os2.h>

ULONG    ulSession;   /*  Session identity of application whose title is requested. */
PSZ      pszTitle;    /*  Window List title. */
ULONG    ulTitlelen;  /*  Maximum length of data returnable, in bytes. */
ULONG    rc;          /*  Return code. */

rc = WinQueryTaskTitle(ulSession, pszTitle,
       ulTitlelen);