Indeed : FOO.hxx: TYPE FOO_TEMPLATE () { TYPE foo; /*...*/ return foo; } Foo.h: #DEFINE FOO_TEMPLATE foo_int #DEFINE TYPE int #include "Foo.hxx"

Indeed : FOO.hxx: TYPE FOO_TEMPLATE () { TYPE foo; /*...*/ return foo; } Foo.h: #DEFINE FOO_TEMPLATE foo_int #DEFINE TYPE int #include "Foo.hxx" #DEFINE FOO_TEMPLATE foo_float #DEFINE TYPE float #include "Foo.hxx" It's a kind of weird and ugly macro trick, bug it can be useful in C when one's need polymorphism and performance (and cannot use C++ at all, which is a far better solution). [Edit:] I realize now it's not polymorphism like said in the article, because the caller had to tell explicitly which foo_xxx to call. But it did provide "polymorphic" code in Foo.hxx (so only one implementation, no repetition). That said, a cast is also explicit.