how to check for how much memory on system c/c++

[monkeyking]

Hi, is there a system independent way of getting the amount of memory on a system using c/c++?

thanks

[dwhitney67]

You can use sysconf() on both Linux and Unix systems. I doubt it will work under an M$ OS.

The API is sysconf(name), where the 'name' I believe you would need are _SC_PHYS_PAGES to get the number of pages of physical memory, and then _SC_AVPHYS_PAGES to get the number of pages of physical memory currently available.

Then a ratio of available memory can be computed...


double percentAvail = double(totalPages - freePages) / double(totalPages) * 100.0;

For Linux, you can also read/parse /proc/meminfo, but sysconf() seems a bit easier. Merely my opinion.


P.S. My 3000th post! :-)

[Mirge]

You can use sysconf() on both Linux and Unix systems. I doubt it will work under an M$ OS.

The API is sysconf(name), where the 'name' I believe you would need are _SC_PHYS_PAGES to get the number of pages of physical memory, and then _SC_AVPHYS_PAGES to get the number of pages of physical memory currently available.

Then a ratio of available memory can be computed...


double percentAvail = double(totalPages - freePages) / double(totalPages) * 100.0;For Linux, you can also read/parse /proc/meminfo, but sysconf() seems a bit easier. Merely my opinion.


P.S. My 3000th post! :-)

Post hoar! :lolflag:

[monkeyking]

You can use sysconf() on both Linux and Unix systems. I doubt it will work under an M$ OS.

The API is sysconf(name), where the 'name' I believe you would need are _SC_PHYS_PAGES to get the number of pages of physical memory, and then _SC_AVPHYS_PAGES to get the number of pages of physical memory currently available.

Then a ratio of available memory can be computed...


double percentAvail = double(totalPages - freePages) / double(totalPages) * 100.0;

For Linux, you can also read/parse /proc/meminfo, but sysconf() seems a bit easier. Merely my opinion.


P.S. My 3000th post! :-)

CONGRATS dwhitney!

I think atleast 100 of these posts must be related to you helping me.
Thanks for you help and advices.

[dwhitney67]

CONGRATS dwhitney!

I think atleast 100 of these posts must be related to you helping me.
Thanks for you help and advices.

You're welcome. By the way, my posts aren't always spot on; I meant to indicate that I was computing the percent of used memory, not the available. #-o

Now that my post has been quoted, I can't change my error.

[supirman]

On linux systems, you can try sysinfo(2).

A quick example to find total RAM:

#include <stdio.h>
#include <sys/sysinfo.h>

int main(void)
{
struct sysinfo myinfo;
unsigned long total_bytes;

sysinfo(&myinfo);

total_bytes = myinfo.mem_unit * myinfo.totalram;


printf("total usable main memory is %lu B, %lu MB\n",
total_bytes, total_bytes/1024/1024);

return 0;

}


See man sysinfo for the rest of the items provided by sysinfo (items such as used ram, # processes, swap size, etc).