The implicit inclusion of source files is a method of finding definitions of template entities. This method is enabled for the compiler by default (see also the option IMPLICIT-INCLUDE on "MODIFY-SOURCE-PROPERTIES") and can be disabled with IMPLICIT-INCLUDE=*NO. When disabling implicit inclusion please check the notes in section "Fundamentals".
When implicit inclusion is enabled, the compiler looks for the definition of a template entity in accordance with the following principle:
If a template entity is declared in a header file named basename.H and no definition for it is available in the compiled source code, the compiler will assume that the definition for that template entity is contained in a source file
which is located as a source program element in the same PLAM library as the header file and
which has the same base name as the header file and a standard suffix that is valid for C++ source files, i.e.:
.C,.CPP,.CXXor.CC(e.g. basename.CC).
Let us assume, for example, that a template entity ABC::f is declared in the header file XYZ.H in the library PLAM.T. If the instantiation of ABC::f is requested on compilation, but no definition of ABC::f exists in the compiled source code, the compiler will search the library PLAM.T for a source file with the base name XYZ and a standard suffix that applies to C++ source files, i.e.: .C , .CPP, .CXX or .CC (e.g. XYZ.CC). If such a file exists, it will be treated as if it were included at the end of the source file.