zeromq/libzmq — pull request #341 by kennytm (2012-05-13 13:05:00+00:00)
Title: Allow the ZMQ_MONITOR code compilable on gcc 4.7 on Linux.

The current ZMQ_MONITOR code does not compile in gcc 4.7, as -pedantic and -Werror are enabled, and ISO C++ doesn't allow casting between normal pointers (void*) and function pointers, as pedantically their size could be different. This caused the library not compilable. This commit workaround the problem by introducing one more indirection, i.e. instead of calling

(void *)listener

which is an error, we have to use

*(void **)&listener

which is an undefined behavior :) but works on most platforms

Also, `optval_ = monitor` will not set the parameter in getsockopt(), and the extra casting caused the LHS to be an rvalue which again makes the code not compilable. The proper way is to pass a pointer of function pointer and assign with indirection, i.e. `*optval_ = monitor`.

Also, fixed an asciidoc error in zmq_getsockopt.txt because the `~~~~` is too long.