I use VisualDSP++ 5.0.10 for SHARC 21489. You find attached to projects doing functional the same. The first project "vdsp5-0-10test" doesn't compile, due to a MISRA 8.4 violation. This is in my opinion correct. The second project "vdsp5-0-10test_v2" compiles. The only difference is, that I moved the extern definition from the libmodule1.h to vdsp5-0-10test_v2.c . So this is only a change for the preprocessor, not for the compiler. In my opinion, the second project shall also report a MISRA 8.4 violation. Is there an error in the VDSP compiler? Or, am I wrong?