Node: PROVIDE, Previous: Simple Assignments, Up: Assignments

### PROVIDE

In some cases, it is desirable for a linker script to define a symbol only if it is referenced and is not defined by any object included in the link. For example, traditional linkers defined the symbol `etext`. However, ANSI C requires that the user be able to use `etext` as a function name without encountering an error. The `PROVIDE` keyword may be used to define a symbol, such as `etext`, only if it is referenced but not defined. The syntax is `PROVIDE(`symbol `=` expression`)`.

Here is an example of using `PROVIDE` to define `etext`:

         SECTIONS
         {
           .text :
             {
               *(.text)
               _etext = .;
               PROVIDE(etext = .);
             }
         }

In this example, if the program defines `_etext` (with a leading underscore), the linker will give a multiple definition error. If, on the other hand, the program defines `etext` (with no leading underscore), the linker will silently use the definition in the program. If the program references `etext` but does not define it, the linker will use the definition in the linker script.