undefined reference to `shm_open'

[Lennart Sorensen]

On Tue, Dec 15, 2009 at 05:31:01PM +0100, Niko Lau wrote:
> 2009/12/15 Lennart Sorensen <lsorense at csclub.uwaterloo.ca>:
> > On Tue, Dec 15, 2009 at 05:16:05PM +0100, Niko Lau wrote:
> >> I want to use the libv4l2 for my arm platform with uclibc cross compiler.
> >> When I link a appl with that lib I get the following error:
> >> arm-linux-uclibc-gcc -Wall -O2 -g -I../libv4l2/include
> >> -L../libv4l2/lib  -o capture capture.c -lv4l2 -lv4lconvert
> >> ../libv4l2/lib/libv4lconvert.so: undefined reference to `shm_open'
> >> collect2: ld returned 1 exit status
> >> make: *** [test] Fehler 1
> >>
> >> The lib is built with the same compiler without any error.
> >> Can someone give me a hint what the problem is. Since it works with a
> >> glibc compiler i think the problem is the uclibc.
> >
> > The man page (for the glibc version) says you have to link with -lrt.
> > I don't see you doing that.  Do you have to?  Does uclibc have such
> > a thing and does it do shm_open?  I guess it must or the header files
> > would have failed yoiur earlier compile already.
> >
> > --
> > Len Sorensen
> >
> 
> The -lrt flag is set during libv4lconvert building. I can see shm_open
> in the include file (/sys/mman.h)
> so i think uclibc has shm_open.

Well I don't see -lrt in the gcc line above.  Fix that and it should
build I suspect.

-- 
Len Sorensen