Re: Call of rmdir in destructor causes InvalidMemoryOperationError

[Daniel Kozak via Digitalmars-d-learn]

Timo Gransch via Digitalmars-d-learn píše v Čt 01. 01. 2015 v 16:14
+0100:
> Hi,
> 
> I have a class which unzips an archive into a temporary directory below the 
> system temp folder. I want to delete this temporary directory in the class's 
> destructor, but when I call rmdir there, I get an
> 
> core.exception.InvalidMemoryOperationError@(0)
> 
> The effect is not limited to this special case. Whenever I call rmdir in the 
> destructor, no matter for which directory, I get the same error.
> 
> Environment: DMD v2.066.1 (from D-Apt) on Ubuntu 14.10 (32 and 64 bit).
> 
> Sample code:
> 
> // -------------------------------------------
> module main;
> 
> import std.stdio;
> import std.file;
> import std.path;
> 
> class RmdirTest
> {
>       private string sTempDir;
> 
>       this(string sInstanceName)
>       {
>               writeln("Constructor called");
>               sTempDir=tempDir() ~ dirSeparator ~ sInstanceName;
>               mkdir (sTempDir);
>       }
> 
>       ~this()
>       {
>               writeln("Destructor called");
> 
>               if (sTempDir !is null)
>               {
>                       rmdir(sTempDir);
>               }
>       }
> }
> 
> void main(string[] args)
> {
>       RmdirTest rmDirTest=new RmdirTest("123");
> }
> // -------------------------------------------
> 
> Console output is:
> 
> Constructor called
> Destructor called
> core.exception.InvalidMemoryOperationError@(0)
> 
> The directory "/tmp/123" is created, but not deleted.
> 
> When I change the line "(sTempDir !is null)" to "((sTempDir !is null) && 
> (exists(sTempDir)) && (isDir(sTempDir)))", the exception is thrown already on 
> this line, so obviously  the problem also applies to other file functions 
> like exists and isDir.
> 
> Is there any solution for this?
> 
> Thanks and best regards,
> Timo
You shoud not use destructor for this operation. In D there is no
guarantee that class destructor will be called. So you can probablly use
struct instead of class or add some method and called it explicitly when
needed