CODEWITHSUNDEEP
c++linkerg++
bra_racing
bra_racing

Reputation: 620

g++ not find .so files

I am trying to generate a c++ library using the g++ compiler. My library has another C library as dependency and I have compiled it in order to obtain the .so files.

I have the following structure:

src:
    include/linux:
        libcustom.a
        libcustom.la
        libcustom.so
        libcustom.so.0
        libcustom.so.0.0.0

Now, when I have all the .o files of my cpp classes, and I want to link the library, I execute the following command:

g++ -shared -L/usr/lib/R/lib -Wl,-Bsymbolic-functions -Wl,-z,relro -o mylibrary.so File1.o File2.o File3.o -L./include/linux -lc++ -lutil -lm -lcustom -Wl,-rpath='$ORIGIN/include/linux' -L/usr/lib/R/lib -lR

But it throws me the error:

libcustom.so.0: cannot open shared object file: No such file or directory

I am executing the command from the src directory.

I know it could be fixed editing the LD_LIBRARY_PATH, but the idea it is someone can use my library without the need of configuring anything, so I am trying to do that with the c++'s -rpath flag.

Any idea how can I fix it, or the reason for the error?

Upvotes: 1

Views: 1959

Answers (1)

gdlmx
gdlmx

Reputation: 6789

The error message you got seems to come from the run-time loader ld.so instead of the linker ld (I know the names are confusing). You have to distinguish between finding so's at link-time and at run-time. The -L flag you give at link-time has nothing to do with localizing the library at run-time.

Your rpath=./include/linux value is not correct, because dot is not recognized by the ld as relative path. Relative searching path should be given like

-Wl,-rpath='$ORIGIN/include/linux'

where the $ORIGIN represents the folder where your executable (not mylibrary.so) locates. Make sure to use single quote and not double quote because the string $ORIGIN should be passed to the linker literally and hard coded into the executable file.

More details goes

  1. how to link to shared lib from shared lib with relative path

  2. ld: Using -rpath,$ORIGIN inside a shared library (recursive)

Upvotes: 3

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