RealView Compilation Tools Compiler Reference Guide - ARM ...

Compiler-specific Features
4.5.9 __attribute__((used))
This variable attribute informs the compiler that a variable is to be retained in the object,
even if it is unreferenced.
Variables marked as used are emitted to a single section, in the order they are declared.
You can specify the section into which variables are placed using
__attribute__((section)).
Note
This variable attribute is a GNU compiler extension that is supported by the ARM
compiler.
Note
Functions might also be marked as used using the corresponding function attribute
__attribute__((used)).
Usage
You can use __attributte__((used)) to build tables in the object.
Example
static int lose_this = 1;
static int keep_this = 2 __attribute__((used)); // retained in object file
static int keep_this_too = 3 __attribute__((used)); // retained in object file
See also
• __attribute__((section)) on page 4-44
• __attribute__((used)) on page 4-35.
4.5.10 __attribute__((weak))
The declaration of a weak variable is permitted, and acts in a similar way to __weak.
• in GNU mode:
extern int Variable_Attributes_weak_1 __attribute__((weak));
• the equivalent in non-GNU mode is:
__weak int Variable_Attributes_weak_compare;
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