Language Environment region control block

Regions are defined to effectively manage the resources for multiple processes, allowing, for instance, for the reuse of resources. There is one RCB per instance of a Language Environment environment and there is no link between RCB in separate Language Environment environments. For mapping information on the RCB, see the SCEEMAC(CEERCB) data set. Figure 1 shows the format of the RCB.

Figure 1. Region control block (RCB) field descriptions

1   CEERCB
      OFFSET   OFFSET
     DECIMAL     HEX  TYPE        LENGTH   NAME (DIM)    DESCRIPTION
    ======== ======== ========= ========   ============= ===============================
           0      (0) STRUCTURE        0   CEERCB        , RCB mapping
           0      (0) BITSTRING      128   CEERCB_EXTERNAL(0)
                                                         External portion in 31-bit mode
           0      (0) CHARACTER        8   CEERCBEYE     eyecatcher 'CEERCB '
           8      (8) CHARACTER       56   *             Reserved for "external" fields
          64     (40) BITSTRING       16   *             Reserved
          80     (50) SIGNED           4   CEERCB_VERSION_ID(0)
                                                         LE Ver., Rel. and Mod.
          80     (50) BITSTRING        1   CEERCBPRODID  Product Number
          81     (51) BITSTRING        1   CEERCBVERID   Version Version Number
          82     (52) BITSTRING        1   CEERCBRELID   Release Release Number
          83     (53) BITSTRING        1   CEERCBMODID   Modification ID
          84     (54) CHARACTER        4   *             Padding
          88     (58) ADDRESS          8   CEERCB_PCBCHAIN
                                                         Address of PCB
          96     (60) CHARACTER       32   *             Reserved End

Figure 2 provides the cross reference to the RCB.

Figure 2. Region control block (RCB) field descriptions (cross reference)

1     CROSS REFERENCE
                                                   HEX          HEX
      NAME                                         OFFSET      VALUE     LEVEL
      ====                                         ======     ========   =====
      CEERCB                                            0                    1
      CEERCB_EXTERNAL                                   0                    2
      CEERCB_PCBCHAIN                                  58                    2
      CEERCB_VERSION_ID                                50                    2
      CEERCBEYE                                         0                    2
      CEERCBMODID                                      53                    2
      CEERCBPRODID                                     50                    2
      CEERCBRELID                                      52                    2
      CEERCBVERID                                      51                    2