How to add 3rd party C library to tensorflow?

Question

I want to add a third-party C library to tensorflow so I can use it in one of the examples. There doesn't seem to be any examples to follow so any assistance would be appreciated.

Here's my work using event2 as the third-party C library.

I've created an 'ln -s' in tensorflow/third_party to provide the event2/ headers:

ls -al ~/code/tensorflow/third_party/event2
lrwxr-xr-x  1 XXXX  staff  25 May 17 16:03 ~/code/tensorflow/third_party/event2 -> /usr/local/include/event2

/usr/local/include> ls event2
BUILD                bufferevent_struct.h event_compat.h       listener.h           thread.h
buffer.h             dns.h                event_struct.h       rpc.h                util.h
buffer_compat.h      dns_compat.h         http.h               rpc_compat.h         visibility.h
bufferevent.h        dns_struct.h         http_compat.h        rpc_struct.h
bufferevent_compat.h event-config.h       http_struct.h        tag.h
bufferevent_ssl.h    event.h              keyvalq_struct.h     tag_compat.h

third_party/event2/BUILD:

licenses(["notice"])

cc_library(
    name = "event2",
    srcs = glob( [ "*.h" ] ),
    visibility = [ "//visibility:public" ],
)

In tensorflow/examples/label_image/BUILD, I added the reference to libevent and my test files that use the events2 library:

cc_binary(
    name = "label_image",
    srcs = [
        "main.cc",
        "my_new_file_using_events.c",
        "my_new_file_using_events.h",
    ],
    linkopts = ["-lm", ],
    copts = [ "-Ithird_party", ],
    deps = [
        "//tensorflow/cc:cc_ops",
        "//tensorflow/core:framework_internal",
        "//tensorflow/core:tensorflow",
        "//third_party/event2:event2",
    ],
)

It compiles fine but when I run the binary I get the following errors:

dyld: lazy symbol binding failed: Symbol not found: _event_base_new
  Referenced from: /Users/XXXX/code/tensorflow/bazel-bin/tensorflow/examples/label_image/label_image
  Expected in: flat namespace

dyld: Symbol not found: _event_base_new
  Referenced from: /Users/XXXX/code/tensorflow/bazel-bin/tensorflow/examples/label_image/label_image
  Expected in: flat namespace

[1]    41395 trace trap  bazel-bin/tensorflow/examples/label_image/label_image

The libevent.a, libevent.dylib and other libevent* libs are in /usr/local/lib. according to nm, event_base undefined.

nm -f label_image | grep event_base
  U _event_base_dispatch
  U _event_base_new

How do I resolve this linkage error? Thanks.

How to add 3rd party C library to tensorflow?

1 Answers