Which Header Files Are Used?

MCU header files are installed in the Device Family Packs (DFPs) which are installed in various locations on your PC:

  • DFP artifacts embedded within a Harmony 3 Project
  • DFP artifacts installed with the compiler
  • DFPs installed/maintained by the IDE

When you build a project in MPLAB® X, which header files are used in the build?

Priority 1 - Search Project Files

The first location searched is the project itself. MPLAB Harmony 3 projects are self-contained. DFPs in the IDE and XC32 are ignored.


Priority 2 - Search IDE-Managed DFPs

If no local header files are found in the project, the DFPs in the IDE are used. The version can be selected in the Project Properties window.


DFPs in the XC compilers are normally ignored unless you override the IDE setting:


Selecting the DFP Version used by the IDE


Click on the current DFP's icon in the Dashboard.



Select a different DFP in Project Properties to use it.


Priority 3 - Search Compiler DFPs

If no other DFP is present, the XC compiler can use its own header files:


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