What exactly are shared libraries?

Chenchu · 11-28-2009, 01:59 PM

I've looked around to find some information on the net about the subject, but I couldn't find reasonable explanation of what are shared libraries?

I mean, I know the general concept of them but I would like to get some information about how they work, why are the used?..
I just want to get this concept settle better in my mind

thanks in advance fellas

MrCode · 11-28-2009, 02:10 PM

EDIT: Sorry, plz ignore (I've left the link up, though). I was being too generic before, and you're asking for specifics...I'm not really that savvy myself

Wikipedia link: Shared libraries.

knudfl · 11-28-2009, 03:40 PM

No harm starting with the generic, others may fill
out what's missing. .. .. Some other "generic" info here :
http://www.yolinux.com/TUTORIALS/Lib...ndDynamic.html

http://tldp.org/HOWTO/Program-Librar...libraries.html

http://www.ibm.com/developerworks/li...ies/index.html
.....
And this one is very general http://www.google.com/linux

http://www.google.com/linux?hl=en&q=...es&btnG=Search
.....

paulsm4 · 11-28-2009, 04:13 PM

One other point worth emphasizing:

Quote:

Windows .dll's have significant differences from *nix .so's

Chenchu · 11-28-2009, 06:29 PM

thanks for all your replies,
so just to see if I got it correct;

a shared library is actually a code [in some form] that a program needs to run properly. now instead of compiling that file into the executable file,
it is located on the disk and shared between all the programs that need it. when the program is executed, it calls the lib file it need and loads it.

?

paulsm4 · 11-28-2009, 06:31 PM

Yup - exactly

There are many advantages to using shared libraries; there are also a number of disadvantages.

In general - especially for "system level" components that are likely to be generally useful, and also likely to evolve over time, "shared libraries" tend to be the way to go.

Chenchu · 11-28-2009, 07:14 PM

ok, thank you.

I also found this link very useful for listing the advandages and disadv of shared lib:

http://www.sunmanagers.org/archives/1995/1602.html