PPT Slide
Variations in Program Loading - Shared Libraries
- Shared library code resides in special “.so” files. For example, “ls -l /lib/libc.*” on xi shows:
-rw-r--r-- 1 bin bin 1153120 Dec 14 1996 /lib/libc.a
lrwxrwxrwx 1 root root 11 Aug 7 1996 /lib/libc.so -> ./libc.so.1
-rwxr-xr-x 1 bin bin 663460 Dec 14 1996 /lib/libc.so.1
- libc.a contains the statically-linked object modules.
- libc.so.1 contains the shared library object modules that are linked dynamically at runtime to a single copy of the routines in memory shared between all processes.
- Result is decrease in overall memory usage.
- Shared lib support requires OS intervention!