What is the difference between __inline__ and inline?

[kent.johnstone_1]

Hi,
What is the difference between "inline" and "inline"?
I have programs with both. "inline" works, "inline" has an error "Unable to resolve identifier inline"

thanks

[kent.johnstone_1]

Sorry, the first inline didn't let me post double underscores before and after as with the fourth and fifth inline.

[Ancient Dragon]

Is this what you mean?

[kent.johnstone_1]

no, __inline__

I would also like to add __always_inline__ to this.

[Ancient Dragon]

might be gcc extension

[kent.johnstone_1]

I read those whole things and still don't understand. Sorry.

[Ancient Dragon]

It's really not all that difficult - the standard inline keyword is SUGGESTION to the compiler to duplicate the function contents each time it appears in the program -- the compiler can coose to ignore inline if it wants to. The gcc extension _always_inline causes thee gcc to duplicate the function all the time, whether optimizing the program or not.

[kent.johnstone_1]

Thank you. Now what's the difference between inline and __inline__?
inline works, __inline__ has an error. I don't really want to be removing the underscores without knowing what they're doing.

[Ancient Dragon]

The way I understand it, __inline__is an older version of the inline keyword -- it was an extension to some compilers. It's pretty much obolete nowdays except for older c89 compilers (link).

[kent.johnstone_1]

Thank you very much Ancient Dragon! That explains a lot.