Messages in this thread | | | Date | Sun, 30 Oct 2005 18:14:31 +0100 | From | Adrian Bunk <> | Subject | Re: [parisc-linux] [2.6 patch] parisc: "extern inline" -> "static |
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On Sun, Oct 30, 2005 at 11:42:52AM -0500, John David Anglin wrote: > > > I really don't think it makes any difference. Such a function (returning > > > always 0) is always going to be inlined, and the only difference between > > > static inline and extern inline is what happens when it can't be inlined. > > > > On !alpha we are defining inline to __attribute__((always_inline)) for > > any non-ancient gcc making this a zero difference. > > It looks as if there are subtle differences between "always_inline" > and "extern inline". From the GCC extensions document: > > [always_inline] > Generally, functions are not inlined unless optimization is specified. > For functions declared inline, this attribute inlines the function even > if no optimization level was specified. > > [extern inline] > If you specify both @code{inline} and @code{extern} in the function > definition, then the definition is used only for inlining. In no case > is the function compiled on its own, not even if you refer to its > address explicitly. Such an address becomes an external reference, as > if you had only declared the function, and had not defined it. > > The primary difference between "static inline" and "extern inline" > is in what happens when the address of the function is referenced. > With "extern inline", you need a unique library function to resolve > external references. With "static inline", you may end up with > multiple copies of a function if its address is taken. >...
In the kernel, "static inline" expands to "static inline __attribute__((always_inline))" and "extern inline" expands to "extern inline __attribute__((always_inline))".
> Dave
cu Adrian
--
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