Re: C++ module initialization and deinitialization doubts
Lance Diduck wrote:
Maxim Yegorushkin wrote:
ALiX wrote:
I'm writing a wrapper around a C++-library. The library provides
datastructures/classes and functions from which I am going to build a
concrete class. The user of my class is not supposed to know about the
library, and unfortunately, the library requires a call to an
initialization function at program start, and a call to a termination
function at program end (both are really necessary in my case). If
possible I would like to avoid such a setup for my users. Is there a
standard solution to this problem? From a lot of postings it seems
there isn't...
One solution known as schwarz counter is used by c++ standard library
to initialize the standard stream objects and it works very well.
Schwarz counter works well when you control the entire build process as
well. If your library is deployed as shared libraries or dll's , then
anticipate more problems with users trying to figure out quirks in
different loaders on different platforms. cout/cin is a special case:
it can be found in every compiler, and a compiler writer could just
start up cout/cin and such as the first thing to do when assembling the
program initialization routines. This is why they don't have problems
with dll's and such.
The only prerequisite for schwarz counter is including a header file
before using the object. That header file contains the schwarz counter
definition along with the object definition. The guarantee given by
schwarz counter is that the initialization function is called by the
translation unit (.o) which gets initialized first during run-time. The
order of initialization in one translation unit is stipulated in the
standard. This guarantees that the object is initialized before its
first use provided that the header file is included before any usage.
From run-time and dynamic linker (loader) perspective, It only requires
that a function must be callable, in other words, function address must
be resolved by the dynamic linker before the first call or when the
first call is done. Are there linkers that support c language while not
resolving functions (and symbols in general) before or while its first
use?
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