CODEWITHSUNDEEP
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Brandon Yates
Brandon Yates

Reputation: 2052

How do I correctly link in static libraries with g++?

I have a rather complex build I'm trying to do, but I'll simplify it a little bit for this question. I have three c++ files (main.cpp file2.cpp and file3.cpp) that I am trying to compile and link against 3 static libs (libx.a liby.z libz.a) to produce an executable.

There are many dependencies involved.

All three c files are dependent on all 3 libs. libx is dependent on liby and libz. And finally, libx is also dependent on several callback functions contained in file2.cpp.

What command line would build this correctly? I have tried dozens of variations and nothing has satisfied the linker yet.

If it matters, the libs are pure c code compiled with gcc. Sources are c++ and I'm compiling/linking with g++. I have this working correctly as a visual studio project, and am trying to port to linux.

Upvotes: 0

Views: 473

Answers (2)

Jay
Jay

Reputation: 9582

You may need to use extern "C" { } in your .cpp files to include the header for the C libs.

See Including C Headers in C++ in How To Mix C and C++.

Upvotes: 0

radical7
radical7

Reputation: 9114

From your post:

g++ main.cpp file2.cpp file3.cpp -lx -ly -lz

However, if static linking is causing you problems, or you need to distribute any of the libs, then you may consider making them shared objects (.so files, commonly called DSOs). In that case, when you build libx.a, for example, compile all the sources to object files, and then combine them with

g++ -shared *.o -o libx.so -ly -lz

(this version assumes that liby.a and libz.a are stills static, and will be combined into libx.so

Upvotes: 2

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