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    SubjectRe: GCC nested functions?
    >>>>> On Wed, 12 May 2004 10:59:24 -0700, Stephen Hemminger <> said:

    Stephen> I used GCC nested functions in the (not released) bridge
    Stephen> sysfs interface for 2.6.6. It seemed like a nice way to
    Stephen> express the sysfs related interface without doing lots of
    Stephen> code copying (or worse lots of macros).

    Oh, man! Nested C functions are evil. Just don't do it.

    Stephen> This works fine for GCC 2.95 and 3.X for i386 and x86_64
    Stephen> architectures, but the ia64 (cross compiler) pukes with:

    Stephen> In function `store_forward_delay':
    Stephen> : undefined reference to `__ia64_trampoline'

    Stephen> Redoing it as separate functions is easy enough, but the
    Stephen> questions are:

    Stephen> - Are gcc nested functions allowed in the kernel? If not
    Stephen> where should this restriction be put in Documentation?
    Stephen> CodingStyles?

    Nested C functions shouldn't be allowed _anywhere_. It's the worst
    extension that has made it into GNU C.

    Stephen> - Or is gcc on ia64 just too stupid? or do some more
    Stephen> support routines need to exist in arch/ia64?

    It has nothing to do with stupidity. The kernel doesn't support all
    the routines provided by libgcc.a. __ia64_trampoline() is one of

    Stephen> - Do other architectures (sparc, ppc) have similar problems?

    It's not a problem. It's a feature. It's likely that other
    architectures which require a helper-routine from libgcc would behave
    the same.

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