Hi,
You can use three Macros in one file which will be compiled. Please refer the following structure.
DEFINE_SOURCE(x_source, cell, thread, dS, eqn)
{
}
DEFINE_SOURCE(y_source, cell, thread, dS, eqn)
{
}
DEFINE_SOURCE(z_source, cell, thread, dS, eqn)
{
}
After compiled the C file, you can see three options in the surce term column.