[fpc-devel] Fix for an annoying error
Michael Van Canneyt
michael at freepascal.org
Tue Nov 30 23:03:35 CET 2021
I removed the $linklib for common.dll.
On Tue, 30 Nov 2021, J. Gareth Moreton via fpc-devel wrote:
> Well, running the program on the target system isn't a guaranteed
> success even if there's no error on the compilation system because the
> DLL in question may be different (or missing).
> If it turns out that common.dll is not required, then the maintainer of
> the package should probably remove the $linklib line, otherwise I'm not
> sure. If I'm right in thinking, if the DLL is missing or incompatible,
> it won't read the exports table and so even if just a warning is raised,
> it may cause a cascade error if any of its functions are used in the
> unit because they're not declared.
> Gareth aka. Kit
> On 30/11/2021 16:22, Michael Van Canneyt via fpc-devel wrote:
>> On Tue, 30 Nov 2021, J. Gareth Moreton via fpc-devel wrote:
>>> That was a conundrum I was trying to answer when making the patch.
>>> What is a warning and what is an error?
>>> A lot of the verification code is dependent on compile-time constants
>>> whose values depend on the compiler's target platform, including
>>> header sizes, so any mismatch is an error case, and the checking of
>>> header sizes and the COFF magic number are done together, since the
>>> correct header size is dependent on the magic number's value.
>>> I didn't look too much further beyond the verification code, but if
>>> it's able to detect if a DLL is 32-bit on a 64-bit system and vice
>>> versa, I feel that's a warning rather than error because, in my
>>> experience, it's down to a default system configuration (I got the
>>> error on a freshly-installed machine) rather than something
>>> untoward. If the DLL is missing, that should probably be a warning
>>> too and I'll see if I can make that change. A corrupted DLL is
>>> definitely an error though.
>>> I didn't do a verification to see if the DLL is for AArch64, for
>>> example, since that situation is more unlikely. It also starts to
>>> bloat the compiler code.
>>> Either way, using a DLL for a different build of Windows is a warning
>>> at the very least because the project will probably break when you
>>> try to run it.
>> Personally, I think that reverting to a warning was a mistake.
>> You have no guarantee that the resulting program will run if you
>> ignore the
>> Not on the system where you compiled, not on the system where you will
>> run the program.
>> For your particular problem: I looked at the source code of the oracle
>> As far as I can see there is no need to include the common.dll in the
>> linklib statements, all that should be linked is the oracle dll. It
>> may be a better solution simply to remove that line.
>> fpc-devel maillist - fpc-devel at lists.freepascal.org
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