According to the SAP documentation:
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System functions are only intended for internal usage. Incompatible changes and further development is possible at any time and without warning or notice.
So calling system C functions using a ``++CALL++`` statement should be avoided.
== Noncompliant Code Example
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CALL 'MULTIPLY' ID 'P1' FIELD '9999'
ID 'P2' FIELD '9999'
ID 'RES' FIELD RESULT.