ARM Compiler toolchain Using the Linker - ARM Information Center

10.26 About embedded symbols
10.26.1 See also
BPABI and SysV shared libraries and executables
You can add specially-named symbols to input objects that cause the linker to create symbol
versions. These symbols are of the form:
• name@version for a non-default version of a symbol
• name@@version for a default version of a symbol.
You must define these symbols, at the address of the function or data, as that you want to export.
The symbol name is divided into two parts, a symbol name name and a version definition version.
The name is added to the dynamic symbol table and becomes part of the interface to the shared
object. Version creates a version called ver if it does not already exist and associates name with
the version called ver.
The following example places the symbols foo@ver1, foo@@ver2, and bar@@ver1 into the object
symbol table:
int old_function(void) __asm__("foo@ver1");
int new_function(void) __asm__("foo@@ver2");
int other_function(void) __asm__("bar@@ver1");
Example 10-3 Creating versioned symbols, embedded symbols
The linker reads these symbols and creates version definitions ver1 and ver2. The symbol foo is
associated with a non-default version of ver1, and with a default version of ver2. The symbol
bar is associated with a default version of ver1.
There is no way to create associations between versions with this method.
Reference
Using the Compiler:
• Using compiler and linker support for symbol versions on page 5-34.
Using the Assembler:
• Chapter 5 Writing ARM Assembly Language.
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