Don't worry pshared semaphore fans, I haven't forgotten about you.
In order to support pshared semaphores, as opposed to global
sem_open semaphores, we need to allow calling programs to allocate the
necessary structures. Currently, librthread hides nearly all
implementation details by exporting only pointer types.
There are a few problems with just pushing the structure definitions
out into the header.
0. It's ugly.
1. Every future implementation change results in a major library
change.
2. Testing changes and rolling them back becomes a serious burden.
If we're going to do this, I think we need to do it the right way.
1. Export opaque storage types, as in
typedef struct _sem_storage {
char payload[64];
} sem_t;
Then librthread will be able to add and shuffle fields inside the
struct as necessary.
2. Do it for all (or most) or most of the types. mutex is the obvious
one.
This is a major flag day for librthread. All the various scripting
modules for python/ruby/perl/lua/etc that require LD_PRELOAD are going
to implode vigorously. Most of the ruby gems I have installed weren't
installed through pkg_add, making this even more of a landmine.
Changing structure sizes goes wrong in far worse ways than adding or
removing symbols.
It would have been nice to ride along the 5.5 time_t reinstall
everything bump, but we missed it. Even so, I think we can only afford
to do this once, and not drag it out in a serious of increments in
which people get burned over and over.
The other solution is to stick with the status quo. pshared semaphores
are the only missing feature that's popped up on my rader. pshared
mutexes have not. And semaphores can be fairly easily switched to
using sem_open. If there are ports that require pshared support, I'd
be happy to help patch them to use sem_open.
