The COBEXIT option indicates which libraries COBOL E15 and E35 exit routines should use when they are executed.
COBEXIT=COB1 specifies that COBOL exits should use either OS/VS COBOL libraries or no libraries at all.
COBEXIT=COB2, the default, specifies that COBOL exits should use VS COBOL II or Enterprise COBOL for z/OS libraries.
VS COBOL II or Enterprise COBOL for z/OS run-time library modules typically require more virtual storage than OS/VS COBOL library modules, and the amount of additional storage depends on VS COBOL II or Enterprise COBOL for z/OS installation options. When VS COBOL II or Enterprise COBOL for z/OS run-time library modules are used, it may be necessary to account for this additional storage by adjusting the b value of the Exit-Name parameter on the MODS statement.
If you install MFX with COBEXIT=COB1 and later wish to change from OS/VS COBOL to either VS COBOL II or Enterprise COBOL for z/OS, you must complete a series of steps. The process includes changing the COBEXIT option to COB2 and installing two additional modules in your SYNCLINK library. Follow Changing Default Option Settings section for more details.