Mapfile structure and syntax

You can enter three types of directives into a mapfile:

• segment declarations

• mapping directives

• size-symbol declarations

Each directive can span more than one line and can have any amount of white space (including new-lines) as long as it is followed by a semicolon. You can enter 0 (zero) or more directives in a mapfile. (Entering 0 directives causes ld to ignore the mapfile and use its own defaults.) Typically, segment declarations are followed by mapping directives. You would declare a segment and then define the criteria by which a section becomes part of that segment. If you enter a mapping directive or size-symbol declaration without first declaring the segment to which you are mapping (except for built-in segments, explained later), the segment is given default attributes as explained below. This segment is then an ``implicitly declared segment.''

Size-symbol declarations can appear anywhere in a mapfile.

The following subtopics describe each directive type. For all syntax discussions, the following apply:

• All entries in constant width, all colons, semicolons, equal signs, and at (@) signs are typed in literally.

• All entries in italics are substitutables.

• { ... } means ``zero or more.''

• { ... }+ means ``one or more.''

• [ ... ] means ``optional.''

• section_names and segment_names follow the same rules as C identifiers where a period (.) is treated as a letter (for example, .bss is a valid name).

• section_names, segment_names, file_names, and symbol_names are case sensitive; everything else is not case sensitive.

• Spaces (or new-lines) may appear anywhere except before a number or in the middle of a name or value.

• Comments beginning with ``#'' and ending at a new-line may appear anywhere that a space may appear.