Cycle detected between modules with ctors/dtors

Steven Schveighoffer via Digitalmars-d-learn digitalmars-d-learn at
Fri Mar 6 14:20:26 PST 2015

On 3/4/15 4:15 PM, rumbu wrote:
> On Wednesday, 4 March 2015 at 16:08:00 UTC, Steven Schveighoffer wrote:
>> curiously not listed? That doesn't make any sense. If there is not a
>> cycle in the listed modules, where at least 2 modules have a static
>> ctor or static dtor, then there is a bug in the cycle detection code.
> Source code is available here:
> The runtime error chain was "system.globalization -> internals.locale ->
> system.runtime.interopservices -> ->
> system.globalization
> Three of these modules import "internals.resources" containing a static
> constructor. The static dtor is in system.runtime.interopservices.

I'll take a look. importing a module that has static ctor/dtor doesn't 
count, it must be in the module itself to be part of the cycle.

>> Clearly, the above is not an issue, but at the moment, the code treats
>> having a ctor and having a dtor as the same thing. How to fix it? I'm
>> not exactly sure, you need to have the modules sorted according to
>> ctor and also according to dtor. The runtime is supposed to run dtors
>> in reverse order from ctor calls, and I think we should not break
>> that. But there is definitely room to allow for reordering when ctors
>> are not affected.
>> I'll have to think about it some more.
> Why bother? I'll leave this to the programmer, he can take full
> responsibility to not mess up module ctors/dtors. I remember the old
> Delphi days where this was assumed from the start: initialization and
> finalization order of execution (equivalent of static ctor/dtor) were
> not guaranteed. It was better to obtain an AccessViolation or a
> StackOverflow and correct the circular reference, instead of a NEVER
> running executable.

Well, 1) because we can fix it, and it's the correct thing to do, and 2) 
because it's an interesting problem (I remember when I fixed the old 
cycle detection code, which was buggy and just printed "cycle detected" 
or some such nonsense, it was a very interesting difficult problem to 


More information about the Digitalmars-d-learn mailing list