The ANTRQST macro can be used to request many different functions. The order that these requests are made and completed is very important. In addition, determining whether your system is capable of providing all of the supported ANTRQST functions is also very important.
The first thing is issuing the ANTRQST REQUEST=LEVEL request to determine the level of support on your system. The SDM API will provide in the RETINFO area the level number indicating the current level of support on your system. See ANTRQST and ANTRQSTL macros – call to the system data mover API to determine the meaning of the level number and what functions are available on your system.
Once you know what functions are available on your system, you can now start invoking the ANTRQST functions. Again, the order these functions are requested and are completed is very important. For example, if you want to make ILK=PPRC requests, you must first issue the ANTRQST macro with the REQUEST=PESTPATH parameter and wait for the request to complete successfully before issuing the ANTRQST macro with the REQUEST=PESTPAIR parameter.
In other words, the SDM address spaces of ANTAS000 and ANTMAIN support multiple simultanous requests. If you were to use ASYNCH=YES and issue the REQUEST=PESTPAIR immediately after the REQUEST=PESTPATH, SDM would possibly process both of these requests at the same time, and potentially the PPRC path may not be established when the establish for the volume pair is sent to the storage control.