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

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

On Thursday, 1 January 2015 at 15:14:41 UTC, Timo Gransch wrote:
> 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)

Destructors are usually called by GC, during a GC cycle, so allocating and deallocating memory is not allowed there. If some function allocates, reallocates or deallocates, it will cause this very error. This means you shouldn't use any functions in a destructor that are not @nogc.

Solution in this case: call rmdir not from destructor.

Am Thu, 01 Jan 2015 16:07:06 +0000
schrieb "thedeemon" <dlang@thedeemon.com>:

> Solution in this case: call rmdir not from destructor.

Thanks (also to Daniel Kozak) for the information. I moved the functionality to an explicitly called method.

Best regards,
Timo