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Linking a shared Python object to cmake, which depends on external libraries

We have a c file called dbookpy.c that will provide Python linking some C functions.

Next, we decided to create the correct .so with cmake, but it seems we are doing something wrong with respect to linking the libdbook library of the external library in the binding:

CMakeLists.txt is as follows:

PROJECT(dbookpy)

FIND_PACKAGE(PythonInterp)
FIND_PACKAGE(PythonLibs)

INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_PATH})
INCLUDE_DIRECTORIES("/usr/local/include")
LINK_DIRECTORIES(/usr/local/lib)
OPTION(BUILD_SHARED_LIBS "turn OFF for .a libs" ON)

ADD_LIBRARY(dbookpy dbookpy)
SET_TARGET_PROPERTIES(dbookpy PROPERTIES  IMPORTED_LINK_INTERFACE_LIBRARIES dbook)
SET_TARGET_PROPERTIES(dbookpy PROPERTIES LINKER_LANGUAGE C)
#SET_TARGET_PROPERTIES(dbookpy PROPERTIES LINK_INTERFACE_LIBRARIES dbook)
#SET_TARGET_PROPERTIES(dbookpy PROPERTIES ENABLE_EXPORTS ON)
#TARGET_LINK_LIBRARIES(dbookpy LINK_INTERFACE_LIBRARIES dbook)

SET_TARGET_PROPERTIES(dbookpy
PROPERTIES
    SOVERSION 0.1
    VERSION 0.1
)

Then build:

x31% mkdir build
x31% cd build 
x31% cmake ..
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Check size of void*
-- Check size of void* - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Configuring done
-- Generating done
-- Build files have been written to: /home/edd/dbook2/dbookpy/build
x31% make
Scanning dependencies of target dbookpy
[100%] Building C object CMakeFiles/dbookpy.dir/dbookpy.o
Linking C shared library libdbookpy.so
[100%] Built target dbookpy

So far so good. Test in Python:

x31% python
Python 2.5.4 (r254:67916, Apr 24 2009, 15:28:40) 
[GCC 3.3.5 (propolice)] on openbsd4
Type "help", "copyright", "credits" or "license" for more information.
>>> import libdbookpy
python:./libdbookpy.so: undefined symbol 'dbook_isbn_13_to_10'
python:./libdbookpy.so: undefined symbol 'dbook_isbn_10_to_13'
python:./libdbookpy.so: undefined symbol 'dbook_sanitize'
python:./libdbookpy.so: undefined symbol 'dbook_check_isbn'
python:./libdbookpy.so: undefined symbol 'dbook_get_isbn_details'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: Cannot load specified object

Hmmm. Linker Error. This doesn't seem to be a libdbook link:

x31% ldd libdbookpy.so
libdbookpy.so:
        Start    End      Type Open Ref GrpRef Name
    05ae8000 25aec000 dlib 1    0   0      /home/edd/dbook2/dbookpy/build/libdbookpy.so.0.1

No, it is not. The correct link to libdbook looks like this:

x31% ldd /usr/local/bin/dbook-test 
/usr/local/bin/dbook-test:
    Start    End      Type Open Ref GrpRef Name
    1c000000 3c004000 exe  1    0   0      /usr/local/bin/dbook-test
    08567000 28571000 rlib 0    2   0      /usr/lib/libm.so.5.0
    09ef7000 29efb000 rlib 0    1   0      /usr/local/lib/libdbook.so.0.1
    053a0000 253d8000 rlib 0    1   0      /usr/lib/libc.so.50.1
    0c2bc000 0c2bc000 rtld 0    1   0      /usr/libexec/ld.so

Does anyone have any idea why this is not working?

Many thanks.

Edd

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2 answers

dbookpy dbook:

target_link_libraries(dbookpy dbook)

ADD_LIBRARY(dbookpy dbookpy) .

, IMPORTED - IMPORTED_LINK_INTERFACE_LIBRARIES :

 Lists libraries whose interface is included when an IMPORTED library target is
 linked to another target.  The libraries will be included on the link line for
 the target.  Unlike the LINK_INTERFACE_LIBRARIES property, this property
 applies to all imported target types, including STATIC libraries.  This
 property is ignored for non-imported targets.

, , "dbook", /usr/local/lib, :

 add_library(dbook SHARED IMPORTED)

, ? , - , CMake, . , dbook ​​, , , . , - , , . .

, , , , find_library(), , /usr/local/lib, .

find_library(DBOOK_LIBRARY dbook REQUIRED)
target_link_libraries(dbookpy ${DBOOK_LIBRARY})

, , .

+3

.

, IMPORTED, , . LINK_LIBRARIES (dbookpy dbook) -ldbook gcc, .

cmake, , LINK_DIRECTORIES -ldbook:

/usr/bin/gcc  -fPIC    -shared -o libdbookpy.so.0.1 "CMakeFiles/dbookpy.dir/dbookpy.o" -ldbook 
/usr/bin/ld: cannot find -ldbook

CMakeList:

PROJECT(dbookpy)
SET(CMAKE_VERBOSE_MAKEFILE ON)

OPTION(BUILD_SHARED_LIBS "turn OFF for .a libs" ON)
ADD_LIBRARY(dbookpy dbookpy)
SET_TARGET_PROPERTIES(dbookpy PROPERTIES LINKER_LANGUAGE C)


FIND_PACKAGE(PythonInterp)
FIND_PACKAGE(PythonLibs)

INCLUDE_DIRECTORIES(${PYTHON_INCLUDE_PATH})
INCLUDE_DIRECTORIES(/usr/local/include)
target_link_libraries(dbookpy dbook)
LINK_DIRECTORIES("/usr/local/lib")

SET_TARGET_PROPERTIES(dbookpy
PROPERTIES
        SOVERSION 0.1
        VERSION 0.1
)

INSTALL(TARGETS dbookpy
        LIBRARY DESTINATION lib
)

?

+1

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