Restrictions

Any fetchable procedure declared with OPTIONS(MAIN) that uses the -cics, -ims, or -mvs compiler options has its own run time context and ON UNIT's memory chains, and its variables are not shared across fetchable boundaries.

Any fetchable procedure that is called from an OPTIONS(MAIN) and compiled and/or linked -cics, -ims, or -mvs must be built using the -bigendian compiler option to avoid any conflicts with variables passed between the main program and fetched subroutines. Using a fetchable where the subroutine's procedure statement uses OPTIONS(MAIN) is not recommended.

For any program which does any form of file I/O, the following needs to be done:

For each FILE declaration it must have storage allocated to its FILE constant. This is achieved through the use of the -defext compile option and/or through the use of an optional parameter called GLOBALDEF. It is important that within a fetchable procedure or a program compiled with OPTIONS(MAIN), this is done exactly one time per FILE constant. If this is not done, the results are completely unpredictable and the behaviors will not be supported.
For typical usage, compiling with -defext is more than adequate. If you have two or more subroutines which are all accessing the same FILE constant, and they are linked into a single fetchable procedure or program, only one of the programs should be compiled with -defext. As an alternative approach you can add the attribute GLOBALDEF to one of the file declarations and not use the -defext switch for any of the compiles.