Syntax

An expression is built up of the following constituents:

expression binop expression
unop expression
expression ? expression : expression
(expression)
number
symbol
func-operator

where binop is one of these binary operators:

+, -, *, /, %, <<, >>, <, >, ==, !=, &, ^, |, &&, ||

where unop is one of this unary operators:

+, -, !, ~

where number is a number, see Numbers in linker configuration files

where symbol is a defined symbol, see define symbol directive and ‑‑config_def

and where func-operator is one of these function-like operators, available in all expressions:

where align and expr are expressions, and region is a region expression, see Region expression.

func-operator can also be one of these operators, which are only available in expressions for the size or alignment of a block or overlay, in check that expressions, and in data expressions in define section directives:

Description

In the linker configuration file, an expression is a 65-bit value with the range -2^64 to 2^64. The expression syntax closely follows C syntax with some minor exceptions. There are no assignments, casts, pre or post-operations, and no address operations (*, &, [], ->, and .). Some operations that extract a value from a region expression, etc, use a syntax resembling that of a function call. A boolean expression returns 0 (False) or 1 (True).