The IGZERREO CSECT provides a method of specifying additional parameters for COBOL to use at runtime. These parameters are separate from the Language Environment runtime options and apply only to the COBOL runtime. These parameters can be used to change the behavior of the COBOL reusable environment, the behavior of nested enclaves in a reusable environment, and the amount of data dumped for BLL cells in a formatted dump.

The parameters for the COBOL runtime environment are specified through IGZERREO using the keyword parameters REUSENV, NESTENC, and DUMPBLL.