pygccxml-development

[pygccxml-development] Call policy for a function returning a map

[Vincent F. <vin...@gm...>]

I'm getting segmentation fault errors trying to replace data in a map.

I've have the following attribute in my class :
    std::map<int,property> properties ;

I get this map from a getter function with the following signature:
    map<int,property> & dataBase::getProperties(void) {
       return properties;
    }

Then the method is called from another class in the C++ code :
    map<int,property> &target=DB.getProperties();

And I try to change data in it :
    target[tmpProperty.id]=tmpProperty;

I get the segmentation fault at this line.
The compiled C++ code is completely working alone, I allready tested it.
I can load a file using one of my functions from C++ directly without
any problem, but when I try to use this same function from Python, I
get this segfault.

I think the problem comes from a bad call policy fro this
getProperties() function, but I'm not really sure.
I'm currently using the following one :
    function.call_policies =
call_policies.return_value_policy(call_policies.reference_existing_object)

Thanks in advance for any help!

Re: [pygccxml-development] Call policy for a function returning a map

[Roman Y. <rom...@gm...>]

On Wed, Jul 30, 2008 at 11:17 AM, Vincent Ferries
<vin...@gm...> wrote:
> I'm getting segmentation fault errors trying to replace data in a map.
>
> I've have the following attribute in my class :
>    std::map<int,property> properties ;
>
> I get this map from a getter function with the following signature:
>    map<int,property> & dataBase::getProperties(void) {
>       return properties;
>    }
>
> Then the method is called from another class in the C++ code :
>    map<int,property> &target=DB.getProperties();
>
> And I try to change data in it :
>    target[tmpProperty.id]=tmpProperty;
>
> I get the segmentation fault at this line.
> The compiled C++ code is completely working alone, I allready tested it.
> I can load a file using one of my functions from C++ directly without
> any problem, but when I try to use this same function from Python, I
> get this segfault.
>
> I think the problem comes from a bad call policy fro this
> getProperties() function, but I'm not really sure.
> I'm currently using the following one :
>    function.call_policies =
> call_policies.return_value_policy(call_policies.reference_existing_object)

http://www.boost.org/doc/libs/1_35_0/libs/python/doc/v2/return_internal_reference.html

In this case return_internal_reference should be used



-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/

[pygccxml-development] Re : Call policy for a function returning a map

[Vincent F. <vin...@gm...>]

Ok, thanks for your answear.

With further investigations, I thing the cause of my problem comes
from the non-call to the constructor when instanciating my class. Some
variables are not initialized and then the program encounters problems
to store datas in unreserved memory. (-> segmentations faults)


I have the following constructor (I simpllify it a little) :

dataBase::dataBase(void) : generic::dataBase() {
   try {
      // Just for debugging purpose
      cout << "Here we are in constructor!" << endl;
      properties.clear();
   }
   catchAll("dataBase::dataBase(void)","");
}


I didn't seem to go through it, the first log sentence was never printed.
I've gone in the associated wrapper class and found this declaration
for the constructor :

struct dataBase_wrapper : postLib::nastran::dataBase, bp::wrapper<
postLib::nastran::dataBase > {

    dataBase_wrapper( )
    : postLib::nastran::dataBase( )
      , bp::wrapper< postLib::nastran::dataBase >(){
        // null constructor

    }

It seems weird to me...
According to me, the instanciation of the corresponding class in
Python should instanciate the underneath class with its defined
constructor...

Is there a bug or am I missing something?
Thanks again!

2008/7/30, Roman Yakovenko <rom...@gm...>:
> On Wed, Jul 30, 2008 at 11:17 AM, Vincent Ferries
> <vin...@gm...> wrote:
>> I'm getting segmentation fault errors trying to replace data in a map.
>>
>> I've have the following attribute in my class :
>>    std::map<int,property> properties ;
>>
>> I get this map from a getter function with the following signature:
>>    map<int,property> & dataBase::getProperties(void) {
>>       return properties;
>>    }
>>
>> Then the method is called from another class in the C++ code :
>>    map<int,property> &target=DB.getProperties();
>>
>> And I try to change data in it :
>>    target[tmpProperty.id]=tmpProperty;
>>
>> I get the segmentation fault at this line.
>> The compiled C++ code is completely working alone, I allready tested it.
>> I can load a file using one of my functions from C++ directly without
>> any problem, but when I try to use this same function from Python, I
>> get this segfault.
>>
>> I think the problem comes from a bad call policy fro this
>> getProperties() function, but I'm not really sure.
>> I'm currently using the following one :
>>    function.call_policies =
>> call_policies.return_value_policy(call_policies.reference_existing_object)
>
> http://www.boost.org/doc/libs/1_35_0/libs/python/doc/v2/return_internal_reference.html
>
> In this case return_internal_reference should be used
>
>
>
> --
> Roman Yakovenko
> C++ Python language binding
> http://www.language-binding.net/
>

Re: [pygccxml-development] Re : Call policy for a function returning a map

[Roman Y. <rom...@gm...>]

On Wed, Jul 30, 2008 at 6:00 PM, Vincent Ferries
<vin...@gm...> wrote:
> Ok, thanks for your answear.
>
> With further investigations, I thing the cause of my problem comes
> from the non-call to the constructor when instanciating my class. Some
> variables are not initialized and then the program encounters problems
> to store datas in unreserved memory. (-> segmentations faults)
>
>
> I have the following constructor (I simpllify it a little) :
>
> dataBase::dataBase(void) : generic::dataBase() {
>   try {
>      // Just for debugging purpose
>      cout << "Here we are in constructor!" << endl;
>      properties.clear();
>   }
>   catchAll("dataBase::dataBase(void)","");
> }
>
>
> I didn't seem to go through it, the first log sentence was never printed.
> I've gone in the associated wrapper class and found this declaration
> for the constructor :
>
> struct dataBase_wrapper : postLib::nastran::dataBase, bp::wrapper<
> postLib::nastran::dataBase > {
>
>    dataBase_wrapper( )
>    : postLib::nastran::dataBase( )
>      , bp::wrapper< postLib::nastran::dataBase >(){
>        // null constructor
>
>    }
>
> It seems weird to me...
> According to me, the instanciation of the corresponding class in
> Python should instanciate the underneath class with its defined
> constructor...
>
> Is there a bug or am I missing something?

I need to see Python code

-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/