This exit routine is scheduled by VTAM® only for environment errors, such as VTAM being inactive or the application program closing its ACB. These situations are marked by a general return code of X'4' and a recovery action return code of X'10'. In such situations, the FDB2 field in the RPL contains a specific error return code that provides further information on the error. Several return codes have been defined for LU 6.2 support. Refer to z/OS Communications Server: SNA Programming for other FDB2 return codes.