Problem migrating to rootcling from rootcint

ROOT
1

Hi ROOT team,

I’m currently trying to port my code over to support ROOT6. I’m currently using boost build to build all my reusable libraries; however, I ran into an issue with generating the dictionaries for ROOT. In order to facilitate a discussion, I’ve created a simple use case that illustrates the issue I’m having.

Consider the following code:

hello.h:

namespace rwk { void hello(); }

hello.cpp

#include <iostream>

namespace rwk
{
    void hello()
    {
        std::cout << "hello 1" << std::endl;
        return;
    }
}

And the associated linkdef.h:

[code]#ifdef CINT

#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;
#pragma link C++ nestedclasses;

#pragma link C++ namespace rwk;
#pragma link C++ function rwk::hello;

#endif[/code]

When I compiled this using ROOT 5.34.00.patches with the following commands, it worked as expected:

[rwk7t@tensor-3 5.34]$  ./build.sh 
rootcint -v3 -f hello_dict.cpp -c -p -I. hello.h linkdef.h
clang++ -c -o hello.o -m64 -std=c++11 -stdlib=libc++ -pipe -W -Woverloaded-virtual -fsigned-char -fno-common -pthread -I. hello.cpp
clang++ -c -o hello_dict.o -m64 -std=c++11 -stdlib=libc++ -pipe -W -Woverloaded-virtual -fsigned-char -fno-common -pthread -pthread -stdlib=libc++ -m64 -I/usr/local/root/5.34.00.patches/include -I. hello_dict.cpp
clang++ -dynamiclib -single_module -Wl,-dead_strip_dylibs -O2 -DNDEBUG -m64 -mmacosx-version-min=10.9 -stdlib=libc+ -o libhello.so -L/usr/local/root/5.34.00.patches/lib -lCore -lCint -lRIO -lNet -lHist -lGraf -lGraf3d -lGpad -lTree -lRint -lPostscript -lMatrix -lPhysics -lMathCore -lThread -lpthread -Wl,-rpath,/usr/local/root/5.34.00.patches/lib -stdlib=libc++ -lm -ldl hello.o hello_dict.o
[rwk7t@tensor-3 5.34]$  root
root [0] gROOT->GetVersion()
(const char* 0x107d9acb1)"5.34/33"
root [1] .L libhello.so 
root [2] rwk::hello()
hello 1

Now, I’m attempting to do the equivalent in root 6.04.00.patches. The changes occur in the linkdef.h (replace CINT with ROOTCLING):

#ifdef __ROOTCLING__

#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;
#pragma link C++ nestedclasses;

#pragma link C++ namespace rwk;
#pragma link C++ function rwk::hello;

#endif

And now, I build as before using rootcling; however, It seems that the dictionaries were not understood by the interpreter.

[rwk7t@tensor-3 6.04]$  ./build.sh 
rootcling -v3 -f hello_dict.cpp -c -p -I. hello.h linkdef.h
clang++ -c -o hello.o -m64 -std=c++11 -stdlib=libc++ -pipe -W -Woverloaded-virtual -fsigned-char -fno-common -pthread -I. hello.cpp
clang++ -c -o hello_dict.o -m64 -std=c++11 -stdlib=libc++ -pipe -W -Woverloaded-virtual -fsigned-char -fno-common -pthread -pthread -stdlib=libc++ -std=c++11 -m64 -I/usr/local/root/6.04.00.patches/include -I. hello_dict.cpp
clang++ -dynamiclib -single_module -Wl,-dead_strip_dylibs -O2 -DNDEBUG -m64 -mmacosx-version-min=10.9 -stdlib=libc+ -o libhello.so -L/usr/local/root/6.04.00.patches/lib -lCore -lRIO -lNet -lHist -lGraf -lGraf3d -lGpad -lTree -lRint -lPostscript -lMatrix -lPhysics -lMathCore -lThread -lpthread -Wl,-rpath,/usr/local/root/6.04.00.patches/lib -stdlib=libc++ -lm -ldl hello.o hello_dict.o
[rwk7t@tensor-3 6.04]$  root
root [0] gROOT->GetVersion()
(const char *) "6.04/01"
root [1] .L libhello.so 
root [2] rwk::hello()
ROOT_prompt_2:1:1: error: 'rwk' is not a class, namespace, or enumeration
rwk::hello()
^
ROOT_prompt_2:1:1: note: 'rwk' declared here

I’ve looked through the docs and forums and I haven’t found a solution. I’ve attached this test code. Can someone pinpoint where I’m going wrong?

Thanks,
Ryan
rootcling_test.tgz (27.5 KB)

2

Hi Ryan,

currently the functions cannot be treated as you do in your example: the situation dramatically improved when pcms are supported.
An easy way out for the moment is to include the hello.h header.

Cheers,
Danilo

3

Include hello.h where?

4

I included it in the hello.cpp:

#include <iostream>
#include "hello.h"

namespace rwk
{
    void hello()
    {
        std::cout << "hello 1" << std::endl;
        return;
    }
}

No change in behavior:

[rwk7t@tensor-3 6.04]$  ./build.sh 
rootcling -v3 -f hello_dict.cpp -c -p -I. hello.h linkdef.h
clang++ -c -o hello.o -m64 -std=c++11 -stdlib=libc++ -pipe -W -Woverloaded-virtual -fsigned-char -fno-common -pthread -I. hello.cpp
clang++ -c -o hello_dict.o -m64 -std=c++11 -stdlib=libc++ -pipe -W -Woverloaded-virtual -fsigned-char -fno-common -pthread -pthread -stdlib=libc++ -std=c++11 -m64 -I/usr/local/root/6.04.00.patches/include -I. hello_dict.cpp
clang++ -dynamiclib -single_module -Wl,-dead_strip_dylibs -O2 -DNDEBUG -m64 -mmacosx-version-min=10.9 -stdlib=libc+ -o libhello.so -L/usr/local/root/6.04.00.patches/lib -lCore -lRIO -lNet -lHist -lGraf -lGraf3d -lGpad -lTree -lRint -lPostscript -lMatrix -lPhysics -lMathCore -lThread -lpthread -Wl,-rpath,/usr/local/root/6.04.00.patches/lib -stdlib=libc++ -lm -ldl hello.o hello_dict.o
[rwk7t@tensor-3 6.04]$  root
root [0] .L libhello.so 
root [1] rwk::hello()
ROOT_prompt_1:1:1: error: 'rwk' is not a class, namespace, or enumeration
rwk::hello()
^
ROOT_prompt_1:1:1: note: 'rwk' declared here
5

Hi Ryan,

apologies: at the interpreter prompt.

Cheers,
Danilo

6

Hi Danilo,

I’m not following – can you be more specific?

I tried this:

root [2] .include hello.h
root [3] .L libhello.so 
root [4] rwk::hello()
ROOT_prompt_5:1:1: error: 'rwk' is not a class, namespace, or enumeration
rwk::hello()
^
ROOT_prompt_5:1:1: note: 'rwk' declared here

-Ryan

7

Hi,

#include "hello.h"
.L libhello.so
rwk::hello()

Cheers,
Danilo

8

yep – that was it!

[rwk7t@tensor-3 6.04]$  root
root [0] #include "hello.h"
root [1] .L libhello.so 
root [2] rwk::hello()
hello 1

Is this a “feature” of ROOT6 or something that will eventually resemble the ROOT5 behavior? It would be inconvenient to have to always add a user defined lib in two steps.

9

Hi Ryan,

for simple functions (non templated, only PODs as arguments) the feature could well appear already in 6.06.

Cheers,
Danilo