Wrong check of mmap() return value in coroutine stack allocator

[Tianlong Wu <rockuw@…>]

In boost source /libs/coroutine/detail/standard_stack_allocator_posix.cpp:120, it has the following snippet:

    void * limit =
# if defined(macintosh) || defined(__APPLE__) || defined(__APPLE_CC__)
    ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
# else
    ::mmap( 0, size_, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
# endif
    ::close( fd);
    if ( ! limit) throw std::bad_alloc();

It assumes that mmap() returns 0 on fail. However when mmap() fails, the return value is NOT 0, but (void*)-1 instead. This wrong check will bypass the throw and let the error pass down, leading to confusing error message seen by the user.

[olli]

test against MAP_FAILED added, thx