Re: pthreads in libtool'd shared library...

[Chris Bowlby]

At 02:44 PM 10/31/2004, Ralf Wildenhues wrote:

> Try adding -no-undefined.  Should fail at library link time then.

This had no effect on the compiler, it still managed to compile with out issue.

> Did you check that the `-pthread' option is really passed to the
> compiler?  I don't have FreeBSD available to test (and no experience
> with it), but online docs suggest it to be sufficient.

The -pthread parameter was being passed to the compiler:

/bin/bash ../../../libtool --mode=link g++  -g -O2   -L/usr/local/lib 
-L/usr/lib -L/usr/compat/linux/lib -o libtest.la -rpath 
/usr/local/data_cop/lib -module -Wsymbolic -pthread -no-undefined 
test.lo  -lc_r -lcrypt -lpq -lcipher
g++ -shared -nostdlib /usr/lib/crti.o 
/usr/lib/crtbeginS.o  .libs/test.o  -L/usr/local/lib -L/usr/lib 
-L/usr/compat/linux/lib -pthread -lcrypt -lpq -lcipher -lstdc++ -lm -lgcc 
/usr/lib/crtendS.o /usr/lib/crtn.o  -Wl,-soname -Wl,libtest.so.0 -o 
.libs/libtest.so.0
(cd .libs && rm -f libtest.so && ln -s libtest.so.0 libtest.so)
(cd .libs && rm -f libtest.so && ln -s libtest.so.0 libtest.so)
creating libtest.la
(cd .libs && rm -f libtest.la && ln -s ../libtest.la libtest.la)


> More random thoughts: try putting -pthread as very last thing on the
>   libtool --mode=links -o libtest.la ...
> cmdline.  Try the g++ link line (which libtool generates) by hand
> and try to see what's necessary to fix it.

Changing the location of where -pthread was, did not help either. But, 
having said that I added -lc_r to the list of parameters and it solved the 
problem, but that only worked when I added it to the raw g++.... command. 
It still seems that libtool is auto-dropping the -lc_r (Which we can see in 
the list of parameters to be added to the command line to g++).... 
preventing it from compiling properly. Even adding it to the LDFLAGS part 
for the sake of testing, libtool stripped it out:

/bin/bash ../../../libtool --mode=link g++  -g -O2   -L/usr/local/lib 
-L/usr/lib -L/usr/compat/linux/lib -o libtest.la -rpath 
/usr/local/data_cop/lib -module -Wsymbolic -pthread -no-undefined 
test.lo  -lc_r -lcrypt -lpq -lcipher

This is the call libtool makes, as we can see -lc_r is part of the 
parameter list here, but:

g++ -shared -nostdlib /usr/lib/crti.o 
/usr/lib/crtbeginS.o  .libs/test.o  -L/usr/local/lib -L/usr/lib 
-L/usr/compat/linux/lib -pthread -lcrypt -lpq -lcipher -lstdc++ -lm -lgcc 
/usr/lib/crtendS.o /usr/lib/crtn.o  -Wl,-soname -Wl,libtest.so.0 -o 
.libs/libtest.so.0

g++ never actually sees it.


> BTW, -Wsymbolic is not mentioned in the online docs.  Is that the same
> as -Bsymbolic?

-B is a path related parameter, -W was mentioned on the dlopen related 
pages so that when I link in my .so library, it already know's about 
symbols in the executable, that might be global. This is only a temporary 
solution until I can clean any of those ones out, and really just to help 
me get the application written faster. Once I've got it written, I'll be 
doing a code review that will clean that requirement out.


> > #libtest_la_LDFLAGS = -version-info
> > $(ABI_CURRENT):$(ABI_REVISION):$(ABI_AGE)
> No need to remove the version-info.


Actually, I got an error when trying to use this line:
libtool: link: CURRENT `' is not a nonnegative integer
libtool: link: `::' is not valid version information
*** Error code 1

and I had not had the chance to look into that yet, was planning on doing 
that later, but if you can suggest a fix that would be great..