Questing about the use of libmm

[Troels Olesen]

Here is an example code of my problem with MMManager* memory leak.

---------------
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <glib.h>

// HACK: 'class' is a reserved keyword in C++
#ifdef __cplusplus
extern "C" {
# define class modemClass
#endif

#include <libmm-glib.h>

#if __cplusplus
# undef class
} //Extern C
#endif

using namespace std;

void GetModemState()
{
     GError *error = NULL;

     // Get Gdbus Connection
     GDBusConnection *connection = g_bus_get_sync(G_BUS_TYPE_SYSTEM, 
NULL, &error);

     if(!connection)
     {
         g_warning("GetModemState : Failed to get gdbus connection");
         g_error_free(error);
     }

     // Get MMModemManager
     MMManager *manager = mm_manager_new_sync(connection, 
G_DBUS_OBJECT_MANAGER_CLIENT_FLAGS_DO_NOT_AUTO_START, NULL, &error);

     if(!manager)
     {
         g_warning("GetModemState : Failed to get MMManager");
         g_error_free(error);
     }

     // Get list of Modems.
     GList *modem_list = 
g_dbus_object_manager_get_objects(G_DBUS_OBJECT_MANAGER(manager));

     // Select first modem. and set it as MMObject.
     MMObject* object = MM_OBJECT(modem_list->data);

     // Get MMModem. (peek)
     MMModem *modem = mm_object_peek_modem(object);

     // Get MMModemState
     MMModemState modem_state = mm_modem_get_state(modem);

     cout << "Modem state is : " << modem_state << endl;

     // Free glist modems.
     g_list_free_full(modem_list, (GDestroyNotify)g_object_unref);

     // Clear pointer referances.
     g_object_unref(manager);
     g_object_unref(connection);
}


int main()
{

     gboolean run = true;
     int count = 0;
     while(run)
     {
         GetModemState();

         cout << "count : " << count << endl;
         if(count > 100000)
             run = false;

         count++;
         //sleep(1);
     }

     return 0;
}
-------------

When this code is run, it leaks about 0,6kb memery pr. loop.


Den 08-02-2016 kl. 09:59 skrev Troels Olesen:
> Hi ModemManager developers.
>
> I have some questions about the how to use the "libmm" library, in an 
> modem handler application.
>
> I have read your API wiki, at 
> "http://www.freedesktop.org/software/ModemManager/libmm-glib/latest/",
> and i have managed to make an application that like mmcli can get 
> information from the ModemManager daemon.
>
> But i have some problems getting updated information from the MM 
> objects i create.
>
> The way i understand the MM object structure is that the MMManager* 
> object gives a list of MMObject*, and from the MMObject* it is 
> possible to get MMModem*, MMModemLocation* and MMModem3gpp* objects 
> witch gives the information that i am searching for.
>
> It is also possible for me to generate these pointer objects, but i 
> have some problems getting them updated, in such a manner that i can 
> run a loop application to check status of the modem.
>
> Especially the function "mm_modem_get_state(MMModem*)", does not seem 
> to update its information, when i run it without resetting all above 
> pointer objects. it this the correct behavior for this function?
>
> Should i consider all MM object pointers as a snapshot frozen in time, 
> from when the MMManager* or MMObject* was generated?
>
> Another problem i have, is understanding the correct clearing/unref 
> procedure for MMManager*, it does not say in the API wiki, if it 
> should be cleared with g_object_unref or NULL, or some other way. an 
> no matter how i try to clear this object it seams that i end up with a 
> memory leak or a double free pointer error.
>
> I hope you can help me.
> Thanks
>
> Troels Olesen.
>
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