warnings during compile of pyzmq

[lookfirst]

I was asked by the pyzmq developer to file this ticket with you.

ubuntu 10.4.1. zeromq 2.0.9

root@ubuntu:~/checkout/pyzmq# python setup.py build_ext --rpath=/usr/local/zeromq --inplace
running build_ext
building 'zmq.zmq' extension
gcc -pthread -fno-strict-aliasing -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fPIC -I/usr/local/zeromq-dev/include -I/usr/include/python2.6 -c zmq/zmq.c -o build/temp.linux-x86_64-2.6/zmq/zmq.o
In file included from zmq/zmq.c:205:
/usr/local/zeromq-dev/include/zmq.h:94: warning: function declaration isn’t a prototype In file included from zmq/zmq.c:206:
/usr/local/zeromq-dev/include/zmq_utils.h:42: warning: function declaration isn’t a prototype gcc -pthread -shared -Wl,-O1 -Wl,-Bsymbolic-functions build/temp.linux-x86_64-2.6/zmq/zmq.o -L/usr/local/zeromq-dev/lib -Wl,-R/usr/local/zeromq -lzmq -o /home/jon/checkout/pyzmq/zmq/_zmq.so

[ellisonbg]

I asked that this be filed here because the warning is coming from the zmq header files.

[sustrik]

Aren't you forward declaring zmq_errno(void) and zmq_stopwatch_start(void) incidentally?

[ellisonbg]

I will check on this...

[ellisonbg]

I don't think we are forward declaring these. What makes you think that?

[sustrik]

It seems that this particular warning is caused by mixing foo() and foo(void) declarations. The explanation seems plausible as the two functions complained about are exactly those that have no arguments.

[ellisonbg]

I just looked and we are following the foo() convention that is in the main header files of zeromq. Should we change this or do you think this would be resolve by a change in zeromq itself?

[sustrik]

No. It should be the same at both places. More investigation needed...

[sustrik]

The problem may be that foo() in C is a different prototype than foo() in C++. Can you point me where the forward declaration in pyzmq is?

[ellisonbg]

We don't really forward declare C functions in pyzmq. We simply include the zmq header file and use the functions. The stuff that appears here:

http://github.com/zeromq/pyzmq/blob/master/zmq/_zmq.pxd#L68

Is not used in any way in the generate C code. It just serves as a hint to the Cython compiler so it can get the types correct.

[sustrik]

Maybe cython transleates foo() in pxd file into foo(void)... Anyway the simplest way to check whether that's the problem would be to change two prototypes in zmq.h (zmq_errno() => zme_errno(void) etc.) and see whether the warnings go away. Can you do that for me?

[ellisonbg]

Yep i will have a look.

[ellisonbg]

This seems to be fixed.