Re: gSystem->Exec() : memory of variables

From: Marc Escalier <escalier_at_lal.in2p3.fr>
Date: Wed, 9 Mar 2011 14:26:17 +0100

Hi,

thanks to the help of many of you, i continue with definition of python, obtaining this :

//begin definition of python :

  gSystem->Setenv("PYTHON_VER","2.6");
  gSystem->Setenv("PYTHON_DIR","'/usr/local/python/python-${PYTHON_VER}'");
  gSystem->Setenv("export PATH","'${PYTHON_DIR}/bin:${PATH}'");
  gSystem->Setenv("export CFLAGS","'-L /usr/local/python/python-2.6/lib'");
  gSystem->Setenv("LD_LIBRARY_PATH","'$PYTHON_DIR/lib:$LD_LIBRARY_PATH'");
 

  // gSystem->Exec("python"); //this commands works   //end definition of python

  //gSystem->Setenv("amiGetDatasetEVNTInfo","'python /afs/cern.ch/atlas/software/releases/16.6.2/AtlasCore/16.6.2/Database/Bookkeeping/AMIClients/pyAMI/python/amiGetDatasetEVNTInfo.py'");   gSystem->Exec("asetup 16.6.2");
  gSystem->Setenv("amiGetDatasetEVNTInfo","python /afs/cern.ch/atlas/software/releases/16.6.2/AtlasCore/16.6.2/Database/Bookkeeping/AMIClients/pyAMI/python/amiGetDatasetEVNTInfo.py");   gSystem->Exec("`echo $amiGetDatasetEVNTInfo`");

but the amiGetDatasetEVNTInfo crashes only because one needs to define asetup 16.6.2, which i can't do *inside* root

---

Axel Naumann a écrit :
> Hi Marc,
>
> That's not what Georg wrote - note the '$' sign.
>
> Anyway, you could probably assign it to a C++ variable and use that,
> instead of an environment variable.
>
> Cheers, Axel.
>
>
> Marc Escalier wrote on 03/09/2011 01:51 PM:
>
>> thanks, i try to do an alias within root :
>> ==>
>>
>> gSystem->Setenv("amiGetDatasetEVNTInfo","'python
>> /afs/cern.ch/atlas/software/releases/16.6.2/AtlasCore/16.6.2/Database/Bookkeeping/AMIClients/pyAMI/python/amiGetDatasetEVNTInfo.py'");
>>
>> gSystem->Exec("`amiGetDatasetEVNTInfo`");
>>
>> gives :
>> sh: amiGetDatasetEVNTInfo: command not found
>>
>> while in unix :
>> ccali16% alias amiGetDatasetEVNTInfo='python
>> /afs/cern.ch/atlas/software/releases/16.6.2/AtlasCore/16.6.2/Database/Bookkeeping/AMIClients/pyAMI/python/amiGetDatasetEVNTInfo.py'
>>
>> ccali16% amiGetDatasetEVNTInfo
>>
>> does something
>>
>> =============================
>> Georg Troska a écrit :
>>
>>> Hi,
>>>
>>> a variable is not an alias.
>>> doing in bash
>>>
>>> # A="xclock"
>>> # echo $A
>>>
>>> will not work either.
>>> Probably not the best way, but
>>>
>>> root[] # gSystem->SetEnv("A","xclock")
>>> root[] # gSystem->Exec("`echo $A`")
>>>
>>> will work.
>>> Georg
>>>
>>>
>>>
>>>
>>>> but the folllowing doesn't "work":
>>>>
>>>> root [1] gSystem->Setenv("amiGetDatasetEVNTInfo","'python
>>>> /afs/cern.ch/atlas/software/releases/16.6.2/AtlasCore/16.6.2/Database/Bookkeeping/AMIClients/pyAMI/python/amiGetDatasetEVNTInfo.py'")
>>>>
>>>> root [2] gSystem->Exec("amiGetDatasetEVNTInfo")
>>>> sh: amiGetDatasetEVNTInfo: command not found
>>>>
>>>> while in unix :
>>>> alias amiGetDatasetEVNTInfo='python
>>>> /afs/cern.ch/atlas/software/releases/16.6.2/AtlasCore/16.6.2/Database/Bookkeeping/AMIClients/pyAMI/python/amiGetDatasetEVNTInfo.py
>>>>
>>>> amiGetDatasetENVInfo
>>>> "works"
>>>>
>>>> would you have a hint ?
>>>>
>>>> ===============
>>>>
>>>> Dario Berzano a écrit :
>>>>
>>>>
>>>>> Hello,
>>>>>
>>>>> each gSystem->Exec(), just like the standard C system() function,
>>>>> opens a new shell ("man system" says /bin/sh) with a brand new
>>>>> environment.
>>>>>
>>>>> But in ROOT you can set environment variables that are seen by
>>>>> subshells launched either via gSystem->Exec() or
>>>>> gSystem->OpenPipe()/GetFromPipe(): for instance you can play with
>>>>> the following code:
>>>>>
>>>>> // The environment variable COUNTER is set to 0
>>>>> gSystem->Setenv("COUNTER", "0");
>>>>>
>>>>> // COUNTER is incremented in subshells and its value is set to ROOT's
>>>>> // (*not* shell's) environment
>>>>> for (Int_t i=0; i<100; i++) {
>>>>> gSystem->Setenv("COUNTER", gSystem->GetFromPipe("expr $COUNTER +
>>>>> 1"));
>>>>> }
>>>>>
>>>>> // A subshell is spawned to echo the value of envvar COUNTER
>>>>> gSystem->Exec("echo Variable COUNTER has value $COUNTER");
>>>>>
>>>>> Please note that opening/closing 100 subshells just to increment a
>>>>> variable's value 100 times isn't very performance-friendly...
>>>>>
>>>>> Cheers,
>>>>> --
>>>>> : Dario Berzano
>>>>> : INFN & Università - Torino, Italy
>>>>> : Wiki: http://newton.ph.unito.it/~berzano
>>>>> : GPG: http://newton.ph.unito.it/~berzano/gpg
>>>>> : Mobile: +39 348 72 22 520
>>>>>
>>>>>
>>>>> Le 9 mars 2011 à 11:53, Marc Escalier a écrit :
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> in root, there are the methods TSystem::Exec() and
>>>>>> TSystem::GetFromPipe which have the same behaviour for the
>>>>>> following issue :
>>>>>>
>>>>>> if one does in unix :
>>>>>> a=3
>>>>>> echo $a
>>>>>> it works
>>>>>>
>>>>>> but in root :
>>>>>> if ones does :
>>>>>> gSystem->Exec("b=3);
>>>>>> gSystem->Exec("echo $b")
>>>>>> it will "forget" the b
>>>>>>
>>>>>> only this works :
>>>>>> gSystem->Exec("c=3;echo $c")
>>>>>>
>>>>>> ==>
>>>>>> is there a way to have the memory of the variables for several
>>>>>> gSystem->Exec() commands ?
>>>>>> (in order to do some instructions ones, and some others inside a loop)
>>>>>>
>>>>>> (i tried also with export, but it doesn't help)
>>>>>>
>>>>>> thanks
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>
Received on Wed Mar 09 2011 - 14:28:22 CET