RE: Floating point differences between executables sharing a dll
I am encountering the following scenario while compiling a project
under Visual Studio 2005 with the floating point model set as precise.
Are these 3 projects all compiled with VC2005?
What is the FP model for each of those projects?
Two executables A and B share a common dll C. Both call the function
func() in C with the same input and get slightly different floating
point results. Below is what func() looks like:
Does anyone know why this is happening?
Disclaimer: this is just a guess at the moment. I may be totally wrong.
Different floating point models have different levels of precision.
IF the DLL is linked against the dynamic CRT, and IF the initialization of
the CRT has a dependency on the FP model, then the behavior of the DLL would
be different between the 2 applications that use the DLL.
The reason is that the dynamic CRT would be loaded and initialized by the
application. this would then also influence the FP functions that are used by
the DLL.
IF this is indeed the case, then you could perhaps solve this by linking the
DLL or the EXE against the static CRT. They would then use separate CRTs.
I will have to do a test to see if this is correct or not.
--
Kind regards,
Bruno.
bruno_nos_pam_van_dooren@hotmail.com
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