node-gyp - not finding library headers

问题:

I'm trying to use a the gstreamer framework in my node addon. I had the following to my to my binding.gyp, but when i run the build command it, the console states that the header is not found. When i compile my gstreamer files outside of node-gyp, it compiles successfully. Does anyone see something wrong with my binding file ?

console

hello.cc3:25: fatal error: gstreamermm.h: No such file or directory 

binding.gyp

{
  "targets": [
    {
      "target_name": "addon",
          "libraries": [
            "-lgstreamer-1.0", "-L/usr/inlcude/gstreamer-1.0/gst/"
          ],
      "sources": [ "hello.cc" ]
    }
  ]
}

compile command that works correctly, and that I'm trying to run

g++ main.c -o main `pkg-config --cflags --libs gstreamer-1.0`

Update: Following @Mike Kinghan binding.gyp

回答1:

Does anyone see something wrong with my binding file?

Yes:

"libraries": [
            "-lgstreamer-1.0", "-L/usr/include/gstreamer-1.0/gst/"
          ],

The "libraries" element, in binding.gyp should include the libraries, specified in -l or absolute filename form, that you want to link.

-lgstreamer-1.0 is one of those. -L/usr/inlcude/gstreamer-1.0/gst/ is not. It is a linker option that will instruct the linker to search for libraries specified in -l form in the directory /usr/include/gstreamer-1.0/gst/.

That is specifying a library search directory, so if it were needed, you should say so in the "library_dirs" element:

"library_dirs": [
  "/usr/inlcude/gstreamer-1.0/gst/",
]

But you don't need it, because there are no libraries in /usr/inlcude/gstreamer-1.0/gst/. All the files under /usr/include are C or C++ header files, not libraries. Libraries are installed under /lib, /usr/lib or /usr/local/lib.

You say you can successfully compile a program with:

g++ main.c -o main `pkg-config --cflags --libs gstreamer-1.0`

That works because as you may know,

pkg-config --cflags --libs gstreamer-1.0

outputs the compiler and linker options needed to build a target that depends on gstreamer-1.0

Let's have a look:

$ pkg-config --cflags --libs gstreamer-1.0
-pthread -I/usr/include/gstreamer-1.0 -I/usr/include/glib-2.0 \
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include \
-lgstreamer-1.0 -lgobject-2.0 -lglib-2.0

Then let's use that information to write binding.gyp. (On your system it might differ from mine):

binding.gyp

{
    "targets": [
    {
        "target_name": "addon",
        "include_dirs": [
            "/usr/include/gstreamer-1.0",
            "/usr/include/glib-2.0",
            "/usr/lib/x86_64-linux-gnu/glib-2.0/include"
        ],
        "libraries": [
            "-lgstreamer-1.0",
            "-lgobject-2.0",
            "-lglib-2.0"
        ],
        "sources": [ "hello.cc" ]
    }
  ]
}

(Have we forgotten the -pthread option emitted by pkg-config? No. node-gyp passes it the compiler and linker by default)

With this binding.gyp, your build should look something like mine:

$ node-gyp configure build
gyp info it worked if it ends with ok
gyp info using node-gyp@3.4.0
gyp info using node@4.7.2 | linux | x64
gyp info spawn /usr/bin/python2
gyp info spawn args [ '/usr/share/node-gyp/gyp/gyp_main.py',
gyp info spawn args   'binding.gyp',
gyp info spawn args   '-f',
gyp info spawn args   'make',
gyp info spawn args   '-I',
gyp info spawn args   '/home/imk/develop/so/scrap/build/config.gypi',
gyp info spawn args   '-I',
gyp info spawn args   '/usr/share/node-gyp/addon.gypi',
gyp info spawn args   '-I',
gyp info spawn args   '/usr/include/nodejs/common.gypi',
gyp info spawn args   '-Dlibrary=shared_library',
gyp info spawn args   '-Dvisibility=default',
gyp info spawn args   '-Dnode_root_dir=/usr/include/nodejs',
gyp info spawn args   '-Dnode_gyp_dir=/usr/share/node-gyp',
gyp info spawn args   '-Dnode_lib_file=node.lib',
gyp info spawn args   '-Dmodule_root_dir=/home/imk/develop/so/scrap',
gyp info spawn args   '--depth=.',
gyp info spawn args   '--no-parallel',
gyp info spawn args   '--generator-output',
gyp info spawn args   'build',
gyp info spawn args   '-Goutput_dir=.' ]
gyp info spawn make
gyp info spawn args [ 'BUILDTYPE=Release', '-C', 'build' ]
make: Entering directory '/home/imk/develop/so/scrap/build'
  CXX(target) Release/obj.target/addon/hello.o
  SOLINK_MODULE(target) Release/obj.target/addon.node
  COPY Release/addon.node
make: Leaving directory '/home/imk/develop/so/scrap/build'
gyp info ok 

Note furthermore, pkg-config tells you that the correct compiler include-path to locate gstreamer-1.0 header files is:

/usr/include/gstreamer-1.0

not:

/usr/incude/gstreamer-1.0/gst/

And we have followed that advice in our binding.gyp. Therefore in your source code you will write, e.g.

#include <gst/gst.h>

and not:

#include <gst.h>

Later

Now your compiler cannot locate <gst/gstconfig.h>

One possible cause is that you didn't faithfully copy the necessary include-directories reported for your system by:

pkg-config --cflags gstreamer-1.0

into the include_dirs list of your binding-gyp. Possibly you just copied the ones from my example. My example, giving directories:

-I/usr/include/gstreamer-1.0 -I/usr/include/glib-2.0 \
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include

was run on Ubuntu 17.04, in which gst/gstconfig.h is in fact installed in /usr/include/gstreamer-1.0. But on Ubuntu 16.04, for example:-

$ pkg-config --cflags gstreamer-1.0
-pthread -I/usr/include/gstreamer-1.0 \
-I/usr/lib/x86_64-linux-gnu/gstreamer-1.0/include -I/usr/include/glib-2.0 \
-I/usr/lib/x86_64-linux-gnu/glib-2.0/include

we get the additional include directory:

/usr/lib/x86_64-linux-gnu/gstreamer-1.0/include

and gst/gstconfig.h is indeed installed there. Check that you are using the correct include directories that pkg-config reports on your system and correct your binding.gyp if necessary.

If you were using the correct pkg-config results, then it would appear that your gstreamer-1.0 dev package has a defective gstreamer-1.0.pc file providing incorrect pkg-config info. To work around that, ask your distro's package manager to show you where the dev package really installed gst/gstconfig.h. E.g. for Ubuntu 16.04:

$ dpkg -L libgstreamer1.0-dev | grep gst/gstconfig
/usr/lib/x86_64-linux-gnu/gstreamer-1.0/include/gst/gstconfig.h

Then add the required path prefix (e.g. /usr/lib/x86_64-linux-gnu/gstreamer-1.0/include) to the include_dirs of your binding.gyp.