[fpc-devel] Fix for an annoying error

[Tomas Hajny]

On 2021-11-30 08:33, J. Gareth Moreton via fpc-devel wrote:


Hi Gareth,

> For a while now I've had problems building the i386-win32 compiler
> under my 64-bit Windows system because one of the packages fails to
> build - this is because it thinks a statically-imported DLL (done
> through $linklib) is invalid. Technically it is, but this system DLL
> (for me, it is named COMMON.DLL and is in one of my system folders, so
> it's not something I can safely modify or replace) is for 64-bit
> Windows and is not recognised when building for 32-bit, and the only
> 'fix' is to comment out the culprit $linklib line in the package
> source.
> 
> I've submitted a merge request that generates a warning instead of an
> error if it detects the DLL is 64-bit for a 32-bit target and vice
> versa.  The checks, however, are very strict (it checks the COFF magic
> number, which contains a platform target, and the size of the optional
> header), and an error is still thrown if the DLL is actually corrupted
> or is for an unknown target.
> 
> A warning is still thrown because the program that uses it may
> malfunction, and might be indicative of a bug or a faulty search path
> for the DLL.
> 
> https://gitlab.com/freepascal.org/fpc/source/-/merge_requests/91

Semantically, what's the difference between the two cases (a DLL for a 
different architecture, or a broken DLL)? In both cases the compiled 
executable may be used on other machines (with proper version of the 
respective DLL), but it will fail when running it on the machine used 
for compilation, correct? Shouldn't the compiler handle both cases the 
same way (possibly issuing a similar warning if the DLL is not found at 
all)?

Tomas