[zeromq-dev] zmq_msg_* functions don't check for message validity

[Martin Sustrik]

Hi Reuben,

> Recently I tracked down a segmentation fault to a zmq_msg_size call on a
> closed message.
> After doing some tests I found that all of the zmq_msg_ functions
> segfault on closed messages,
> and I wonder why those functions don't check for the message validity.
>
> Pieter said that 3.0 added checks for sockets and contexts, so adding to
> the messages as well sounds reasonable.

The problem with zmq_msg_t is that it's on the critical path. The 
structure itself is very compact and has no space for a runtime tag. 
Also the code dealing with it is highly optimised and presumably should 
not do any additonal memory access operations.

However, if there's strong need for this kind of functionality, we can 
allow it to be switched on at the compile time, say when --enable-debug 
is used.

Martin