HP-UX Reference (11i v1 05/09) - 5 Miscellaneous Topics (vol 9)

p
pthread_stubs(5) pthread_stubs(5)
$ ld -b -o lib2.sl -lpthread lib2.o
$ cc +DA2.0W thread.c -L. -l1 -l2
$ a.out
Error
$ ldd a.out
lib1.sl => ./lib1.sl
lib2.sl => ./lib2.sl
libc.2 => /usr/lib/pa20_64/libc.2
libpthread.1 => /lib/pa20_64/libpthread.1
libdl.1 => /usr/lib/pa20_64/libdl.1
$ LD_PRELOAD="/lib/pa20_64/libpthread.1" a.out
Success
a.out
correctly lists -lpthread for a threaded application.
$ ld -b -o lib1.sl lib1.o
$ ld -b -o lib2.sl -lpthread lib2.o
$ cc +DA2.0W thread.c -L. -l1 -l2 -lpthread
$ a.out
Success
$ ldd a.out
lib1.sl => ./lib1.sl
lib2.sl => ./lib2.sl
libpthread.1 => /usr/lib/pa20_64/libpthread.1
libc.2 => /usr/lib/pa20_64/libc.2
libpthread.1 => /lib/pa20_64/libpthread.1
libdl.1 => /usr/lib/pa20_64/libdl.1
Example 4 (archived libc)
If the link line of your shared library contains -lc to explicitly link in libc, remove
-lc.Otherwise,
shared libraries may be referencing
libc.2 while the a.out may refer to an older (archived) libc ver-
sion. Thus the application will actually be using two different versions of libc and possibly mixing the code.
This may cause compatibility problems. Basically, an application or library should never directly link
against libc. All programs need to be linked against libc (which the compiler does automatically), so a
shared library will always have the interfaces it needs to execute properly without needing to specify
-lc
on the link line.
SEE ALSO
chatr(1), ld(1), ldd(1), pthread(3T), shl_load(3X), dld.sl(5).
Section 5−−292 Hewlett-Packard Company − 7 − HP-UX 11i Version 1: September 2005