1. Introduction

A MAINSAIL program is a collection of independently compiled MODULEs. The MODULEs are not linked before execution into a single unit as is common for most programming languages. Instead, MAINSAIL dynamically brings MODULEs into memory as needed and takes care of intermodule communication in a machine-independent manner.

The chief outputs of the MAINSAIL compiler are:

• objmod (“object MODULE”): a data file that contains the executable code for a MAINSAIL MODULE.

• intmod (“intermediate MODULE”): a text file that encodes information about the MODULE, used by programs such as the compiler, disassembler, and debugger.

MAINSAIL directly executes objmods (they are not linked with a linkage editor). An intmod is produced only if certain non-default compiler options are set, as described later in this document.

Intmods are portable files; an intmod produced on one system may be used (for the same target) on another system. Intmods are target-specific; an intmod compiled for one target operating system cannot be used in compiling for another operating system. Some care must be used in shipping intmods from one system to another, as they may contain special characters that do not appear in ordinary text files; they should therefore be shipped as binary or (in MAINKERMIT) PTEXT files.