> > gcc -Wall -W -fPIC -shared -o library.so test.c -lc -Wl,-e,my_main > > This is a workable approach, but my_main must act as the entry point of > the program. The entry point is not called with argc and argv. Take a > look at crt1.o on your system to see what the entry point must do. Ah, makes sense. > > gcc -fPIC -fPIE -pie -o library.so test.c > > That does not make a shared library. I'm curious, why not? It's position independent. "file" says it's a shared object: $ file ./library.so ./library.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.9, not stripped > > This can read arguments fine, but dlsym() fails: > > > > ./library.so: undefined symbol: my_func > > You can probably fix that problem by linking with -rdynamic. Didn't work, unfortunately, same problem. > Perhaps we should ask: why do you want an executable shared library? 1) So that like libc, users of my library can determine the library version by just running it. 2) For a particular convoluted use case, where an app using the library could fork() and then exec() the library. 3) Because it can be done :) Thanks -Mayank
