Using Extern C function compiler generates duplicate variables.

[guillegiraldo@…]

When using an external C function, the simulation returns the following error:

Error: Error building simulator. Build log: gcc    -falign-functions -msse2 -mfpmath=sse      -I"C:/OpenModelica1.9.6//include/omc/c" -I. -DOPENMODELICA_XML_FROM_FILE_AT_RUNTIME  -c -o IntegrateInterpolatedExternalVector.o IntegrateInterpolatedExternalVector.c
gcc    -falign-functions -msse2 -mfpmath=sse      -I"C:/OpenModelica1.9.6//include/omc/c" -I. -DOPENMODELICA_XML_FROM_FILE_AT_RUNTIME  -c -o IntegrateInterpolatedExternalVector_functions.o IntegrateInterpolatedExternalVector_functions.c
gcc    -falign-functions -msse2 -mfpmath=sse      -I"C:/OpenModelica1.9.6//include/omc/c" -I. -DOPENMODELICA_XML_FROM_FILE_AT_RUNTIME  -c -o IntegrateInterpolatedExternalVector_records.o IntegrateInterpolatedExternalVector_records.c
gcc    -falign-functions -msse2 -mfpmath=sse      -I"C:/OpenModelica1.9.6//include/omc/c" -I. -DOPENMODELICA_XML_FROM_FILE_AT_RUNTIME  -c -o IntegrateInterpolatedExternalVector_01exo.o IntegrateInterpolatedExternalVector_01exo.c
gcc    -falign-functions -msse2 -mfpmath=sse      -I"C:/OpenModelica1.9.6//include/omc/c" -I. -DOPENMODELICA_XML_FROM_FILE_AT_RUNTIME  -c -o IntegrateInterpolatedExternalVector_02nls.o IntegrateInterpolatedExternalVector_02nls.c
IntegrateInterpolatedExternalVector_functions.c: In function 'omc_VectorTable_destructor':
IntegrateInterpolatedExternalVector_functions.c:14: error: redeclaration of '_table_ext' with no linkage
IntegrateInterpolatedExternalVector_functions.c:13: note: previous declaration of '_table_ext' was here
IntegrateInterpolatedExternalVector_functions.c:17: error: void value not ignored as it ought to be
mingw32-make: *** [IntegrateInterpolatedExternalVector_functions.o] Error 1
mingw32-make: *** Waiting for unfinished jobs....
RESULT: 2

I went to file IntegrateInterpolatedExternalVector_functions.c (attached) and found that variables are actually being declared twice.

[guillegiraldo@…]

Source code to reproduce behavior. Need to change c file path in mo file.

[guillegiraldo@…]

Generated c file with duplicate variable definition (lines 13-16)

[Martin Sjölund]

It is declared twice because you used table on both left side and in the call to the destructor. The destructor function does not have any outputs anyway, so leave that out.

Before:

  function destructor "Release storage"
    input VectorTable table;
    external "C" table=destroyVectorTable(table)

Fixed:

  function destructor "Release storage"
    input VectorTable table;
    external "C" destroyVectorTable(table)

I believe generating code for table twice if it occurs twice in the external call to be an error (Modelica spec seems to allow this use-case).