libgdal.so android 错误：无法加载库“libgdal.so.1”

Question

My problem is the following: I have succesfully built GDAL 1.10.1 using an Android toolchain (CC=i686-linux-android-gcc, CXX=i686-linux-android-c++) that produces the following output libraries libgdal.a , libgdal.la , libgdal.lai , libgdal.so , libgdal.so.1 , libgdal.so.1.17.1 in the output folder .libs (in the following I'll call this folder $GDAL_LIB_PATH ).

I am trying to build a simple Android app (a simple widget application with a QPushButton named TestAndroid ) using Qt 5.4 on Windows. If I don't use GDAL everything works fine and I am able to run my app on an Android emulator for all available platforms: x86 , armeabi and armeabi-v7 .

Nonetheless, if I try to use GDAL (ex. by simply calling GDALAllRegister() in the initialization of the app) and then linking to libgdal.so the application crashes with the following error:

E/art ( 1614): dlopen("/data/app/org.qtproject.example.TestAndroid-1/lib/x86/libTestAndroid.so", RTLD_LAZY) failed: dlopen failed: could not load library "libgdal.so.1" needed by "libTestAndroid.so"; caused by library "libgdal.so.1" not found

I have verified that the Android platform is the right one (x86), otherwise the linker would skip the wrong libgdal.so object.

I have included libgdal.so in the *.apk (generated by Qt) using ANDROID_EXTRA_LIBS *= $GDAL_LIB_PATH/libgdal.so . The other files libgdal.so.xx cannot be included in the same way since Qt prevents it.

In order to avoid dynamic linking I have also tried to link my app with libgdal.a but many link-time errors appears (ex. undefined reference to 'atof')

I have searched on the web but I have not found a solution to my problem.

I am not constrained to use dynamic linking so, a solution to any of the following problems is good for me:

1. Is there a way to avoid the creation of libgdal.so.xx files when building GDAL ?

2. Is there a way to include libgdal.so.xx files in the *.apk file generated by Qt ?

3. How can I avoid link-time errors when linking the static library libgdal.a ?

Thanks in advance for any reply!

Answer 1

After several days of trials and errors (mainly errors) I have found a solution to my problem.

I'm writing it as an answer to my question so that it may be helpful to others.

The problem was during the link-time of GDAL . Briefly: the linker created the "real name" shared library libgdal.so.1.17.1 together with the links to it libgdal.so.1 and libgdal.so .

For some reasons (which I ignore) forcing the link to libgdal.so , the linker searches for libgdal.so.1 (which, in turn, would have searched for libgdal.so.1.17.1 ).

The workaround that solved my problem can be summarized in the following steps:

1. In the GDAL root, run the ./configure according to the desired configuration (see http://trac.osgeo.org/gdal/wiki/BuildingForAndroid ) checking that libtool is ENABLED

2. Edit the created libtool file (eg with gedit ) as follows:

   • replace the value of library_names_spec with library_names_spec="\\$libname\\${shared_ext}"
   • replace the value of soname_spec with soname_spec=""

3. Type make

In the output folder .libs/ the only libgdal.so will be created and now the link to libgdal.so seems to work fine.