You can use the command function form for service requests in a program function by using the call format of ISPEXEC. Excluding calls in FORTRAN, Pascal, and APL2®, the general call format for invoking ISPF services from program functions by using ISPEXEC is:

CALL  ISPEXEC (buf-len, buffer);

These services are not available when you use CALL ISPEXEC, but are available when you use ISPLINK:

  GRERROR      VDELETE
  GRINIT       VMASK
  GRTERM       VREPLACE
  VCOPY        VRESET
  VDEFINE