Dave, the -l switch is clear. The static and dynamic libraries are still vague. Is the behaviour of a dynamic library similar to what VMS does when you link an object file to one of the RTL libraries? Which means it gets linked to an entry point and you can upgrade the RTL and the executable will keep working (provided the entry point is still there)? A static library's behaviour is like linking with object libraries where part of the library is copied into the resulting .exe file? Hans -----Oorspronkelijk bericht----- Van: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] Namens Dave McGuire Verzonden: dinsdag, april 2012 20:29 Aan: hecnet at Update.UU.SE Onderwerp: Re: [HECnet] building simh On 04/10/2012 02:26 PM, H Vlems wrote: yes I know you did but the terms static and dynamic library just didn't register. Ahh ok. Do you understand the difference now? If not I can type up an explanation of how it all works. Are .so and .a libraries interchangeable for the linker, i.e. would this have worked too: NETWORK_OPT = -DUSE_NETWORK -isystem /usr/local/include /usr/lib/libpcap.so This is compiler-dependent, but it generally should work. The "proper" way to link against a library, though, is to use "-l<libname>" on the link command. -Dave -- Dave McGuire, AK4HZ New Kensington, PA