topic Re: shared objects in Operating System - Linux

shared objects

lara — Tue, 09 Sep 2003 20:27:25 GMT

Hi,

Is there a way to find whether an object(.o file ) is compiled with -pic or not.

Regards,
Lara

Re: shared objects

Stuart Browne — Wed, 10 Sep 2003 02:58:01 GMT

Not 100% sure I'm afriad, but by doing some tests locally, using '-fPIC' (as '-pic' using a modern gcc doesn't work), with the tool 'readelf', a -fPIC binary has references to "_GLOBAL_OFFSET_TABLE_", where as an object compiled without -fPIC doesn't..

I've not done enough programming to actually know what '-pic' or '-fPIC' are supposed to do..

Re: shared objects

lara — Wed, 10 Sep 2003 15:22:14 GMT

Seems to be not neccessarly true. Anyway thanks for your suggestion.

Lara

Re: shared objects

lara — Wed, 10 Sep 2003 15:22:52 GMT

Seems to be not necessarly true. Anyway thanks for your suggestion.

Lara

Re: shared objects

Umapathy S — Wed, 10 Sep 2003 15:48:51 GMT

Lara,
I dont have a linux box nearby to test it. But in hpux the file command gives out "relocatable" for position independent code. As you might be aware for the shared libs you need to have PIC.
Just compile a c file both ways and test it on the box.

HTH,
Umapathy

Re: shared objects

lara — Thu, 11 Sep 2003 06:26:00 GMT

Umapathy,

relocatable need not necessarly mean the object file has position independent code.

Lara