How to get info of available heap memory?

[MHermann]

Hi,
I am running an application on Raspberry pi.
Now I would like to be save that there is no OOM (out of memory).
Is it possible to get info of application's available heap memory?

Kind regards,
MHermann

[J.Hilk]

@MHermann on raspberry pi there should be sysconf available

but that only gives you the potential available memory

you should listen to the bad alloc throws of your c++ application or, if you're compiling without exceptions, check for nullptr after the new call

[MHermann]

@J-Hilk said in How to get info of available heap memory?:

but that only gives you the potential available memory

Potential available memory is not very helpful.
I either need to know the used memory or the available memory.
I want to print out the values in a logfile, so that I can check the logfiles after crash.

So could be a way to do a (unnecessary) malloc, check the return and directly free it?
But this solution seems not to be very nice...

[J.Hilk]

@MHermann well I did some more research for you,

seems like there is https://libstatgrab.org a cross platform c library, that gives feedback about the system status

available memory free memory and used memory among them.

[jeremy_k]

@MHermann said in How to get info of available heap memory?:

Hi,
I am running an application on Raspberry pi.

The subtleties of any answer is also going to depend on the operating system, rather than merely the hardware platform.

I either need to know the used memory or the available memory.

As of when? Presuming a multitasking operating system, any information about the state of the system is likely stale for anything but the highest priority task in a hard realtime system.

[MHermann]

@J-Hilk: Thank you very much. I will directly have a look at it.

[MHermann]

@jeremy_k : I am using Raspbian Buster.
I thought when it would be possible to output the used and available memory cyclic, then I could see if the used memory is steadily increasing.

[MHermann]

@J-Hilk said in How to get info of available heap memory?:

@MHermann well I did some more research for you,
seems like there is https://libstatgrab.org a cross platform c library, that gives feedback about the system status
available memory free memory and used memory among them.

I donwloaded statgrab, compiled and installed it.
Now I would like to use it in my source code, but I get following error message after compilation:

libstatgrab.so: file not recognized: file format not recognized

I have to cross compile it for Raspbian buster.
I did following:

./configure --host=arm-linux-gnueabihf  --prefix="/xxx/statgrab"
make
sudo make install

But it seems to be wrong.
Any ideas what I did wrong?

[J.Hilk]

@MHermann see here for a very similar question:
https://forum.qt.io/topic/109732/so-format-not-recognized

@JonB is very spot on with his post

[MHermann]

@J-Hilk: I saw this post already.
I got this info:

libstatgrab.so.10.0.2: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=2052c1fe0c5bbac74534fcf47c64bcd5f6e57164, with debug_info, not stripped

[JonB]

@MHermann said in How to get info of available heap memory?:

I have to cross compile it for Raspbian buster.

I am not an expert, but isn't RPi arm64 architecture rather then x86/x64?

[MHermann]

@JonB: Yes , right.
I thought I can configure this by

./configure --host=arm-linux-gnueabihf

But that seems to be wrong.

[JonB]

@MHermann
I wouldn't know, but I think this would explain the
libstatgrab.so: file not recognized: file format not recognized
message, if that is an x86/x64 file on an arm_64 platform, that was all.

[MHermann]

@JonB: Yes. I think also that this is the problem.

I compiled it directly on the Raspberry Pi.
Now I can compile my application with statgrab.