panel 1:

Most programs on Linux use a bunch of C libraries.

Some popular libraries:

openssl (for SSL!)
sqlite (embedded db?)
zlib (gzip!)
lib pcre (regular expressions!)
libstdc++ (C++ standard library!)

panel 2:

There are 2 ways. to use any library:
1. Link it into your binary
your code (big binary with lots of things!) | zlib | sqlite
and
2. Use separate shared libraries
your code
zlib
sqlite
(all different files)

panel 3:

Programs like this
your code | zlib | sqlite
are called “statically linked”

programs like this your code
zlib
sqlite
are called “dynamically linked”

panel 4:

person 1: how can I tell what shared libraries a Program is using?
person 2: Idd!!

libz.so.1 => /lib/x86-64...  
lib resolv.so.2 =>....  
libc.so.6 =>... 

+34 more

panel 5:

person 1: I got a “library not found” error when running my binary?!

person 2: If you know where the library is, try setting the LD_LIBRARY_PATH environment variable

dynamic linker: LO-LIBRARY_PATH tells me where to look!

panel 6: Where the dynamic linker looks

1. ODT. RPATH in your executable
2. LD- LIBRARY_PATH
3. DT- RUNPATH in executable
4. /etc/ld.so.cache.
   (run Idconfig -p to See contents)
5. /lib, /usr/lib