Recompile plugin macro when source changes

ROOT
1

Hi,
I have an interactive appli in which a user-supplied analysis class is
loaded using the plugin mechanism, i.e. I add dynamically a handler for the class like this:

gROOT->GetPluginManager()->AddHandler("BaseClassName", "UserClassName", "UserClassName", "UserClassName.cpp+", "UserClassName()");

then I check the compilation & (if it works) load it using

TPluginHandler* ph = (TPluginHandler*)gROOT->GetPluginManager()->FindHandler("BaseClassName", "UserClassName");
if( !ph->CheckPlugin() && !ph->LoadPlugin() ) {
   BaseClassName* obj =  (BaseClassName*)ph->ExecPlugin(0);
}

This basically happens when the user hits the “Process” button in
a GUI, in order to run her analysis.

The problem is that if, after a first successful compilation & load of the user’s code, the user then changes her code & hits “Process” again, the class is not recompiled, and the user unwittingly re-executes exactly the same analysis as before.

How can I make this happen ? I think I have found the way to make it recompile the code every time:

gSystem->Unload("UserClassName_cpp.so");
gROOT->GetPluginManager()->RemoveHandler("BaseClassName", "UserClassName");
TClass::RemoveClass(TClass::GetClass("UserClassName"));

but this is not what I want. How can I get it to recompile the code
only when the code changes ?

Cheers
John

2

John,

Simply use ACLIC

If the cpp file is not modified since the previous call, the corresponding shared lib will be dynamically linked, otherwise the file will be recompiled.

Rene

3

Dear Rene,

Thanks for the reply, of course if things were that simple I would do as you suggest! :smiley:
Unfortunately, for various reasons, I need to use plugins. Is there a way to get the same behaviour with a plugin ?

Thanks
John

4

Hi John,

[quote]
How can I make this happen ? I think I have found the way to make it recompile the code every time: [/quote]This is strange, given your code, I would expect the library to be recompiled only on demand (which your proposed work-around).

Can you provide me with a complete running example?

Thanks,
Philippe

5

Hi Philippe,

In fact, you’re absolutely right! :blush:
I attach a fully-functioning version of my code,
to use it do:

+L BaseClass.cpp+
+L GetInstanceOfUserClass.cpp+

Then to test it do:

TObject*obj=0
obj=GetInstanceOfUserClass("DerivedClass","BaseClass")
delete obj
obj=GetInstanceOfUserClass(...
etc. etc.

Only when one modifies DerivedClass.cpp is it recompiled.
It’s perfect!
Thanks a lot
Cheers
John
GetInstanceOfUserClass.cpp (3.82 KB)
DerivedClass.h (439 Bytes)
DerivedClass.cpp (693 Bytes)
BaseClass.h (399 Bytes)
BaseClass.cpp (590 Bytes)