Building an Erlang drivers failed on Apple Silicon

[amitabhadatta14]

Hi,

I am trying to build an Erlang driver with IBM MQ client calls and it is failing to resolve some calls from erl_driver. Please see the below error logs:-

amitabhadatta@VL-MWLGJ26CQ4 c_src % gcc -I /opt/mqm/inc  -I /usr/local/lib/erlang/usr/include  -o mq_series_drv.so mq_series_drv.c -fpic -shared -L /opt/mqm/lib64 -L /usr/local/lib/erlang/lib -L /usr/local/lib/erlang/lib/erl_interface-5.5.1/lib  -lei -lmqic_r -lpthread
ld: Undefined symbols:
  _driver_alloc, referenced from:
      _mq_drv_start in mq_series_drv-1e7a57.o
      _do_connect in mq_series_drv-1e7a57.o
      _do_put in mq_series_drv-1e7a57.o
      _do_get in mq_series_drv-1e7a57.o
      _alloc_and_decode_binary in mq_series_drv-1e7a57.o
      _handle_get in mq_series_drv-1e7a57.o
  _driver_async, referenced from:
      _do_connect in mq_series_drv-1e7a57.o
      _do_put in mq_series_drv-1e7a57.o
      _do_get in mq_series_drv-1e7a57.o
  _driver_free, referenced from:
      _mq_drv_stop in mq_series_drv-1e7a57.o
      _ready_async in mq_series_drv-1e7a57.o
      _ready_async in mq_series_drv-1e7a57.o
      _do_put in mq_series_drv-1e7a57.o
      _do_get in mq_series_drv-1e7a57.o
      _do_free in mq_series_drv-1e7a57.o
      _do_free in mq_series_drv-1e7a57.o
      ...
  _driver_output, referenced from:
      _ready_async in mq_series_drv-1e7a57.o
      _error_bad_arg in mq_series_drv-1e7a57.o
      _return_error in mq_series_drv-1e7a57.o
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Please advise.

your help is appreciated.

[jhogberg]

This is an issue tracker, not a support forum. Try https://erlangforums.com/ :)

[amitabhadatta14]

This is an issue with the Erlang distribution in MacOS. ERL_DRIVER doesn't included in libel.a library, where as we have no issues in linux version.

[jhogberg]

No. libei has nothing to do with drivers, and the error is reported by the linker because you have failed to tell it what to do with undefined symbols. You must add some flags to make the linker on MacOS behave like the Linux one, as the defaults are different on each OS. This has nothing to do with Erlang as such.

Had you asked on the forum instead of opening a ticket, someone would already have told you which flags to use. The issue tracker is not for asking for help, and is in either case only checked on weekdays and then mostly during European working hours.

For what it's worth, the documentation mentions which additional flags you need on MacOS:

If you develop linked-in drivers (shared library) you need to link using gcc and the flags -bundle -flat_namespace -undefined suppress. You also include -fno-common in CFLAGS when compiling. Use .so as the library suffix.