Callable Services Library Routines
Before attempting to call CSL routines from a high-level language, check the reference manual for the language to determine whether such calls are supported and what setup operations are required.
Assembler language programs can call CSL routines from AR mode using
either the MVS/ESA level of the CALL macro or using the CMS preferred
interface group fast path
macro CSLFPI.
The CMS services called through these interfaces are performed in primary space mode. All parameters specified as storage addresses are considered to refer to the primary address space of the user's virtual machine.