Mapfile option

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 zero 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 sections 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 bold-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.