[Bug hurd/4822] grow_heap: static linking warns about madvise() not implemented

["tschwinge at sourceware dot org" <sourceware-bugzilla at sourceware dot org>]

http://sourceware.org/bugzilla/show_bug.cgi?id=4822

Thomas Schwinge <tschwinge at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |VERIFIED
                 CC|                            |tschwinge at sourceware dot
                   |                            |org

--- Comment #4 from Thomas Schwinge <tschwinge at sourceware dot org> 2012-02-17 07:57:12 UTC ---
(In reply to comment #2)
> Should be fixed in trunk, but I didn't actually try to compile for Hurd.

I fixed it up for you in commit 9078ce930afda8bbcba6fe860a13ca62abcf2742.
;-)

Errors and warnings were:

    gcc-4.4 malloc.c [...]
    [...]
    In file included from ../include/sys/mman.h:2,
                     from malloc.c:1754:
    ../misc/sys/mman.h:95: error: expected identifier or '(' before 'void'
    ../misc/sys/mman.h:95: error: expected ')' before '(' token
    [...]
    make[3]: ***
[/media/erich/home/thomas/tmp/glibc/debian/madvise/eglibc-2.13/build-tree/hurd-i386-libc/malloc/malloc.o]
Error 1
    make[3]: Leaving directory
`/media/erich/home/thomas/tmp/glibc/debian/madvise/eglibc-2.13/malloc'
    make[2]: *** [malloc/subdir_lib] Error 2

(Poor GCC, seeing that ``prototype''.)  After fixing that:

    In file included from malloc.c:2567:
    arena.c: In function 'shrink_heap':
    arena.c:823: warning: left-hand operand of comma expression has no effect
    arena.c:823: warning: left-hand operand of comma expression has no effect
    malloc.c: In function 'mTRIm':
    malloc.c:5874: warning: left-hand operand of comma expression has no effect
    malloc.c:5874: warning: left-hand operand of comma expression has no effect

Now the situation is as follows:

    $ echo 'int main() { }' | gcc -o /dev/null -x c -
    $ echo 'int main() { madvise (); }' | gcc -o /dev/null -x c -
    $ echo 'int main() { }' | gcc -o /dev/null -static -x c -
    $ echo 'int main() { madvise (); }' | gcc -o /dev/null -static -x c -
    /tmp/cce05X6t.o: In function `main':
    :(.text+0x7): warning: warning: madvise is not implemented and will always
fail

That is, in the -static case, we only get the warning if madvise is
actively being used in the user code, but not due to glibc's own usage in
malloc.


Joseph already had amended the NEWS file.


Samuel, you can now replace the Debian glibc patch with
d2c736f809690dd69f1cade53a61b99e401bb0e3 and
9078ce930afda8bbcba6fe860a13ca62abcf2742.

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