COMSOL 6.4 - How to Compile and Link an External Material Model

How to Compile and Link an External Material Model

To export functions from the DLL when using Microsoft Visual Studio to compile your library, you must declare the functions as __declspec(dllexport). Therefore, to write a source code that works across platforms, use the following #define pattern:

#ifdef _MSC_VER

#define EXPORT __declspec(dllexport)

#else

#define EXPORT

#endif

EXPORT <return_type> eval(<arguments>) { }

Compiling and Linking

To compile the function into a library, place it in a file (here called ext.c as an example) and proceed as follows depending on the platform:


	See www.comsol.com/system-requirements for information about supported compiler versions.

•

64-bit Windows with Microsoft Visual Studio 2022:

Start > > > from the Windows Start menu.

cd to the directory that contains ext.c.

cl /MT /c ext.c

link /OUT:ext.dll /DLL ext.obj

•

64-bit Linux with Intel Compiler:

cd to the directory that contains ext.c.

icx -fPIC -c ext.c

icx -shared -fPIC -o ext.so ext.o -ldl

•

64-bit Linux ARM64 with GCC:

cd to the directory that contains ext.c.

gcc -fPIC -c ext.c

gcc -shared -fPIC -o ext.so ext.o -ldl

•

64-bit macOS (Intel or ARM64) with Clang:

cd to the directory that contains ext.c.

clang -fPIC -c ext.c

clang -shared -fPIC -o ext.dylib ext.o

For other compilers, refer to the compiler’s documentation for instructions on how to compile and create a shared library.

Linking with Utility Functions

To use the provided utility functions in your external material function, you need to reference a header file that contains the utility function declarations. Add the following line to your file (again, called ext.c as an example):

#include "csextutils.h"

Proceed as follows, depending on the platform:

•

64-bit Windows with Microsoft Visual Studio 2022:

Start > > > from the Windows Start menu.

cd to the directory that contains ext.c

cl /MT /c ext.c /I C:\Program Files\COMSOL\COMSOL64\Multiphysics\data\extmat

link /OUT:ext.dll /DLL ext.obj
C:\Program Files\COMSOL\COMSOL64\Multiphysics\data\extmat\win64\csextutils.lib

•

64-bit Linux with Intel Compiler:

cd to the directory that contains ext.c

icx -fPIC -c -I/usr/local/comsol64/multiphysics/data/extmat ext.c

icx -shared -fPIC -o ext.so ext.o
-L/usr/local/comsol64/multiphysics/lib/glnxa64 -lcsextutils

•

64-bit Linux ARM64 with GCC:

cd to the directory that contains ext.c

gcc -fPIC -c ext.c

gcc -shared -fPIC -o ext.so ext.o -ldl

•

64-bit macOS (Intel or ARM64) with Clang:

cd to the directory that contains ext.c

clang -fPIC -c -I/Applications/COMSOL64/Multiphysics/data/extmat ext.c

clang -shared -fPIC -o ext.dylib ext.o
-L/Applications/COMSOL64/Multiphysics/lib/maci64 -lcsextutils

For other compilers, refer to the compiler’s documentation for instructions on how to compile and create a shared library.