Re: inline functions with gnu99

[Ben Pfaff]

John Darrington <address@hidden> writes:

> Interesting.  I never knew there was more than one interpretation.
>
> To me, the inline keyword is a hint to the compiler that it might be
> better to replace any calls to the function concerned with the body of
> the function, rather than making a subroutine. 
>
> What else might it mean?

That is always what "inline" means at the highest level.  But GCC
and C99 "inline" have different linkage semantics.  Here is some
information on the difference:
        http://gcc.gnu.org/ml/gcc/2006-11/msg00006.html

Here is an excerpt from the GCC 4.3 manual, in the node titled
"Inline", that talks about the static inline case:

     GCC implements three different semantics of declaring a function
    inline.  One is available with `-std=gnu89' or `-fgnu89-inline' or when
    `gnu_inline' attribute is present on all inline declarations, another
    when `-std=c99' or `-std=gnu99' (without `-fgnu89-inline'), and the
    third is used when compiling C++.

[...]

     The three types of inlining behave similarly in two important cases:
    when the `inline' keyword is used on a `static' function, like the
    example above, and when a function is first declared without using the
    `inline' keyword and then is defined with `inline', like this:

         extern int inc (int *a);
         inline int
         inc (int *a)
         {
           (*a)++;
         }

     In both of these common cases, the program behaves the same as if you
    had not used the `inline' keyword, except for its speed.

-- 
Ben Pfaff 
http://benpfaff.org