# Additional Information for OpenVMS Programmers

There is some additional information on compiling and multi-threading that can be useful to VMS programmers.

Compile

On OpenVMS platforms, EMS programmers must define the C-compile command appropriately.

For the VSI C compiler:

    $ CC :== CC/FLOAT=IEEE/IEEE_MODE=UNDERFLOW_TO_ZERO -
    /PREFIX=ALL/INCLUDE_DIRECTORY=("/tibems/include",[])

Link

EMS API libraries are multi-threaded, so OpenVMS scheduler upcalls can yield significant performance improvements:

    $ LINK/THREADS_ENABLE=UPCALLS

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