问题
If I compile my source code with "-L." the dynamic library libmd5.so can be found.
gcc main.c -g -O2 -Wall -o main -L. -lmd5 -lcr
But if I leave the "-L."-option away, the linker does not find the dynamic library. How can I change that without having to invoke "-L."?
(additional info libmd5.so and libmd5.so.1.0.1 are located in /home/user/ba)
回答1:
There's really nothing wrong with the -L flag, so you shouldn't try so hard to get rid of it - is it at runtime you have problems, as the system won't load the libraries you link to ? Here's some options :
- Add /home/user/ba to /etc/ld.so.conf (or similar for your OS) and run ldconfig afterwards. This will be system wide.
- Set the LIBRARY_PATH(for link time) and LD_LIBRARY_PATH(for run time) environment variable.
export LD_LIBRARY_PATH=/home/user/baandexport LIBRARY_PATH=/home/user/ba.This will have effect only for the current shell. - Set the rpath in the executable (you still need the
-L .here though). Add-L /home/user/ba -Wl,-rpath,/home/user/bato your linker flags. This will have effect only for the executable you're making. - Place your shared libraries in a system wide library search path such as
/usr/lib. This will be system wide.
The above have effect at runtime as well - it'll try to find libmd5.so in /home/user/ba or other library search paths for the system when you run the app as well.
回答2:
you can set the LIBRARY_PATH environment variable.
export LIBRARY_PATH=/home/user/ba
来源：https://stackoverflow.com/questions/3374767/gcc-linkage-option-l-alternative-ways-how-to-specify-the-path-to-the-dynamic-l