Re: [Boost-users] [boost] [interprocess] Semaphore cleanup after crash

From: peter_foelsche_at_[hidden]
Date: 2008-07-29 17:00:14

Microsoft has a lot of faults but when comparing Windows API to the LINUX API I take windows every day.

I remember having to clean up shared memory segments by and then under some UNIX OS -- I guess it was SOLARIS.

I also remember that mmap()/munmap() (on SOLARIS) did not behave in a manner, which I would prefer as a C++ programmer, since multiple calls to mmap() could be undone by a single call to munmap(). I hope that this problem was considered when writing the memory mapped io features of boost. I guess you would need some static container of all pointers returned by mmap() and some reference count indicating how often the matching pointer was returned by mmap():

static std::map<void*, size_t> s_sMmap2RefCount;

I also remember the amount of code I wrote to hack around the UNIX feature of killing processes which write to a dead pipe.

I also remember the amount of code I wrote to get the errno from execvp() into the process which called fork().

I also remember having to write code in C instead of C++, since the code was supposed to be linked into a shared library which was intended to be dlopen-ed by some third party executable which in turn may or may not be loading the correct C++ library -- consider that UNIX knows only about a single namespaces for all symbols in a process.

I also remember that I could not write C++ code with a post-C++-Exception-Handling-style, since the matching compiler did not implement C++ Exception Handling correctly for a couple of years after this feature was already working on Windows and OS/2. The UNIX compiler did call destructors for memory locations for which no constructor had been called and vs. versa, they were forgetting to call destructors for initialized temporary objects.

I hate the UNIX API because I'm a C++ programmer.