Re: link with C runtime library

From:

"Bo Persson" <bop@gmb.dk>

Newsgroups:

microsoft.public.vc.language

Date:

Sun, 3 Feb 2008 13:11:46 +0100

Message-ID:

<60lpahF1ro52lU1@mid.individual.net>

George wrote:

Hello everyone,

I am studying the manual for DLLMain, it is mentioned,

http://msdn2.microsoft.com/en-us/library/ms682583.aspx

--------------------
If your DLL is linked with the C run-time library (CRT), the entry
point provided by the CRT calls the constructors and destructors
for global and static C++ objects. Therefore, these restrictions
for DllMain also apply to constructors and destructors and any code
that is called from them. --------------------

My questions are,

1. How could I know if a project whether DLL or EXE or static lib
is linked with C Runtime library?

If you don't know, it probably will call some CRT functions.

2. Why we need C Runtime library in a C++ project? We need to call
some legacy C functions like printf other than pure C++ functions
std::cout?

std::cout is likely to access some C level I/O functions, because the
default is that C++ has to synchronize its use with C. However, your
DLL probably shouldn't do I/O anyway.

The restrictions seems to be that DLL init code shouldn't call other
DLLs or do anything that requires thread synchrinization. This is
similar to global variabels in different translation units having an
undefined initialization order, so they cannot depend on each other.

3. If we use default entry point in DLL (DllMain), does it mean C
Runtime Library is dynamically linked?

I belive that choice is part of the project settings, and does not
depend in the entry point.

Bo Persson