关于Linux中的共享库，是否可以选择库中的导出功能？

Question

I read the tutorial here: http://www.techytalk.info/c-cplusplus-library-programming-on-linux-part-two-dynamic-libraries/

It looks to me there is no functionality like dllexport of DLL in Windows platform.

Is there some way to select certain functions within the library as export function and make the rest functions in the library remain invisible to external call?

Answer 1

You may want to use the visibility function attribute of GCC.

See GCC visibility wikipage and read Drepper's paper How To Write Shared Libraries

Answer 2

There are multiple ways to do this.

Either use the visibility function attribute as mentioned in Basiles answer or use a linker version script to do the job.

In a linker script you list all the functions that you want to export. Here is an example:

File: MyLinkerScript.exp

{
global: 
  myExportedFunction1;
  myExportedFunction2;
  myExportedFunction3;
local: *;
};

During the link step of your shared library you just pass the following extra parameters to gcc:

-Wl,--version-script=MyLinkerScript.exp

Afterwards all symbols in the shared library will be private except for those listed in the global section of your version script.