static) one, in that it can coexist in the same program with one external definition and any number of internal and inline definitions of the same function in other translation units, all of which can differ. This is a separate consideration from the linkage of the function, but not an independent one. C compilers are afforded the discretion to choose between using inline and external definitions of the same function when both are visible.
This describes a feature of programming languages where a single function can be defined multiple times within a program, each with its own implementation. This is distinct from how functions are linked together but not independent of that linkage. C compilers have the option to choose between using inline or external definitions for the same function when both are visible.