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The source files must first be compiled, after which the result of the compilation is put in library form for the linker. These libraries are then linked with a compiled main program to form an executable load module.
On most sites, all the MODULEF libraries are separate (one source file and one compiled and linked file per library). However, in certain cases, it is preferable to group certain linked libraries in order to form one single one (the source libraries remaining separate to facilitate maintenance). This can sometimes result in a reduced CPU time and number of input/output operations during linking, while at the same time facilitating the user task. Furthermore, this grouping of libraries is obligatory by certain linkers which only allow a limited number of libraries.
On the other hand, certain machines have limits regarding the size of the resulting file, or with respect to the number of members per library.
The person in charge of installation must therefore choose the optimal configuration for his/her site. As an example, the following possibilities may be considered:
In addition, on certain systems the result of the linking depends on the order in which the libraries are given (in the case of CDC, CRAY 1, SUN, etc.). The ideal order (if it is not obligatory) is that which enables the linker to read each library only once to resolve the external references (search for missing subroutines). To this end, the MODULEF libraries are ordered with the aid of program PROIMP (see section 4.5, command BB).
The result of this sort is given in the file in Appendix E