C and C++

To facilitate calls between assembler and C or C++, include the following directives in your C or C++ code:

In C: #pragma linkage(,OS)
In C++: extern "OS"

Using either of these directives will result in the compiler generating code that uses the OS linkage convention. In this case, register 1 will contain the address of a list of addresses of the actual arguments. The last address in this list has its high order bit set. For more information, refer to the descriptions of these directives in z/OS XL C/C++ Language Reference.