## Display Device Driver Reference for OS/2

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### .PMI Language Constructs + Imported Functions

This method represents a compromise between the two implementations discussed previously.

The method is applicable for vendors who require code reuse with small maintenance effort, but have performance-sensitive chip sets on board. Another example would be chip vendors who are handling a number of different adapter implementations with a single PMI file. Such PMI files could have common PMI sequence-based SetMode, UnLock and Cleanup functions, but adapter-specific functions, such as DAC and clock-chip programming, could be imported from an external binary object. Porting mixed PMI files to another operating system platform requires porting of the source code only.

External binary objects are 32-bit dynamic libraries, which have to provide instance initialization and export all of the functions that are referenced in the .PMI file. See Include Files in PMI Language Elements and PMI Sections for more detail.

Note: The imported library (OEMPMI.DLL) that is shipped with the IBM Developer Connection Device Driver Kit for OS/2 illustrates the importing functions.