CODEWITHSUNDEEP
c++gccstatic-linking
singingsingh
singingsingh

Reputation: 177

GCC linker error while compiling a static library

I want to create a static library of all my files so that i could give my mylib.a file to others to execute on their system. I use opencv library in my code. I used the following command to compile my code.

g++ index.cpp -o display1 -Wl,-Bdynamic pkg-config --cflags --libs opencv -lglut -lGL -lGLU -Wl,-Bstatic mylib.a

But it is giving the following error. 

/usr/bin/ld: cannot find -lgcc_s
collect2: ld returned 1 exit status

Upvotes: 2

Views: 1184

Answers (1)

Jan Hudec
Jan Hudec

Reputation: 76386

I believe the Kerrek SB is right in the comment. The command should be

g++ index.cpp -o display1 mylib.a $(pkg-config --cflags --libs opencv) -lglut -lGL -lGLU

Explanation:

  • The -Wl,-Bdynamic and -Wl,-Bstatic flags are useless. The linker automatically picks static or dynamic library depending on what it finds. If you give it path to a library (as you do with mylib.a) it can't choose and will link the library you provided. If you give it an -lX flag, it will look for libX.so or libX.a and link whichever it finds, but most Linux installations won't have static variants of system libraries, so there is nothing to choose from either.
  • It's worse, the -Wl,-Bdynamic and -Wl,-Bstatic are wrong. -Wl,-Bstatic prohibits linking of shared libraries. That has the side-effect of selecting static libgcc, which implicitly comes last on the linker command line. And you don't seem to have that installed. Most Linux systems don't.
  • Each object must be listed on the command-line before the libraries it refers to. I would expect mylib.a contains functions that need opencv or opengl, so it must be listed before those -l flags.

Upvotes: 4

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