Memory leak while using CORBA

# 7 years ago
TCS_GMRT	Hi all, We have a device server having TIME (Tango::DevString) attribute to which system time is written at every 1 sec. Here is the syntax we are using to write value to it. Initialized with NULL pointer inside init_device(). `attr_TIME_read = NULL;` Value assigned inside TangoTimeDS::read_TIME(Tango::Attribute &attr) `// str contains system time in string format string str = "2016-10-31 13:01:12"; if ( attr_TIME_read != NULL ){ free( attr_TIME_read ); } attr_TIME_read = CORBA::string_dup( str.c_str() ); // Memory leaks detected by valgring attr.set_value(attr_TIME_read);` Device server is working fine but memory keeps increasing slowly. valgrind shows above commented line to cause memory leakage. I am not getting what is going wrong. Would anyone please provide suggestion/solution to get leak stop increasing? Thanks and Regards, TCS-GMRT Regards, TCS_GMRT

# 7 years ago

Hi all,

We have a device server having TIME (Tango::DevString) attribute to which system time is written at every 1 sec. Here is the syntax we are using to write value to it.
Initialized with NULL pointer inside init_device().


        *attr_TIME_read = NULL;

Value assigned inside TangoTimeDS::read_TIME(Tango::Attribute &attr)


        // str contains system time in string format
        string str = "2016-10-31 13:01:12";
        if ( *attr_TIME_read != NULL ){
		free( *attr_TIME_read );
	}
	*attr_TIME_read = CORBA::string_dup( str.c_str() );   // Memory leaks detected by valgring
        attr.set_value(attr_TIME_read);

Device server is working fine but memory keeps increasing slowly.
valgrind shows above commented line to cause memory leakage.
I am not getting what is going wrong.

Would anyone please provide suggestion/solution to get leak stop increasing?

Thanks and Regards,
TCS-GMRT

Regards,
TCS_GMRT

# 7 years ago
Reynald	I suggest to use CORBA::string_free() instead of free() since this is what should be used when you want to free memory allocated with CORBA::string_dup(). By the way, I would also suggest to use Tango::string_dup() instead of CORBA::string_dup() which does currently invoke CORBA::string_dup() under the hood. This will make your code compatible with future versions of Tango which will be able to use a communication layer based on something different than CORBA. You can try to use Tango::string_free() too but I think this one was introduced recently so it might not be available in the Tango version you are using. Rosenberg's Law: Software is easy to make, except when you want it to do something new. Corollary: The only software that's worth making is software that does something new.

# 7 years ago

Reynald

I suggest to use CORBA::string_free() instead of free() since this is what should be used when you want to free memory allocated with CORBA::string_dup().
By the way, I would also suggest to use Tango::string_dup() instead of CORBA::string_dup() which does currently invoke CORBA::string_dup() under the hood. This will make your code compatible with future versions of Tango which will be able to use a communication layer based on something different than CORBA.
You can try to use Tango::string_free() too but I think this one was introduced recently so it might not be available in the Tango version you are using.

Rosenberg's Law: Software is easy to make, except when you want it to do something new.
Corollary: The only software that's worth making is software that does something new.

# 7 years ago
TCS_GMRT	Hi Reynald, Thanks for your prompt response. I have already tried both way to free memory (free() and CORBA::string_free()). But both doesn't work. Even I tried using Tango::string_dup() (which internally uses CORBA::string_dup() ) but that doesn't work too. Is there any alternative way to assign value to Tango::DevString without using CORBA::string_dup()? Thanks & Regards, TCS-GMRT Regards, TCS_GMRT

# 7 years ago

TCS_GMRT

Hi Reynald,

Thanks for your prompt response.
I have already tried both way to free memory (free() and CORBA::string_free()). But both doesn't work.
Even I tried using Tango::string_dup() (which internally uses CORBA::string_dup() ) but that doesn't work too.

Is there any alternative way to assign value to Tango::DevString without using CORBA::string_dup()?

Thanks & Regards,
TCS-GMRT

Regards,
TCS_GMRT

# 7 years ago
Reynald	Do you free this memory in your delete_device() method too? If yes, can you please post the valgrind report and your code? Rosenberg's Law: Software is easy to make, except when you want it to do something new. Corollary: The only software that's worth making is software that does something new.

# 7 years ago
nleclercq	> Is there any alternative way to assign value to Tango::DevString without using CORBA::string_dup()? I would say "no" since the omniORB implementation of the CORBA API works smoothly for years. BTW, valgring is sometimes wrong…

# 7 years ago
Manu	Hello, May be this HowTo page could help Good luck Emmanuel