How to get current CPU and RAM usage in C++?
There is an open source library that gives these (and more system info stuff) across many platforms: SIGAR API
I've used it in fairly large projects and it works fine (except for certain corner cases on OS X etc.)
There is not a platform independent function for this that I know of. IF you plan to target multiple versions of Windows be aware that the implementation differs across some versions. I hit this problem when testing an app under NT 3.51 for instance... (archaic, I know).
Here is some code I used for the memory side of things. This doesn't work across platforms other than windows, and will just return 0 when compiled without the WIN32 define:
EDIT: I forgot to mention, this code divides and rounds down to the nearest MB, hence the >> 20 all over the place.
// get memory info...
int getTotalRAM()
{
int ret = 0;
#ifdef WIN32
DWORD v = GetVersion();
DWORD major = (DWORD)(LOBYTE(LOWORD(v)));
DWORD minor = (DWORD)(HIBYTE(LOWORD(v)));
DWORD build;
if (v < 0x80000000) build = (DWORD)(HIWORD(v));
else build = 0;
// because compiler static links the function...
BOOL (__stdcall*GMSEx)(LPMEMORYSTATUSEX) = 0;
HINSTANCE hIL = LoadLibrary(L"kernel32.dll");
GMSEx = (BOOL(__stdcall*)(LPMEMORYSTATUSEX))GetProcAddress(hIL, "GlobalMemoryStatusEx");
if(GMSEx)
{
MEMORYSTATUSEX m;
m.dwLength = sizeof(m);
if(GMSEx(&m))
{
ret = (int)(m.ullTotalPhys>>20);
}
}
else
{
MEMORYSTATUS m;
m.dwLength = sizeof(m);
GlobalMemoryStatus(&m);
ret = (int)(m.dwTotalPhys>>20);
}
#endif
return ret;
}
int getAvailRAM()
{
int ret = 0;
#ifdef WIN32
DWORD v = GetVersion();
DWORD major = (DWORD)(LOBYTE(LOWORD(v)));
DWORD minor = (DWORD)(HIBYTE(LOWORD(v)));
DWORD build;
if (v < 0x80000000) build = (DWORD)(HIWORD(v));
else build = 0;
// because compiler static links the function...
BOOL (__stdcall*GMSEx)(LPMEMORYSTATUSEX) = 0;
HINSTANCE hIL = LoadLibrary(L"kernel32.dll");
GMSEx = (BOOL(__stdcall*)(LPMEMORYSTATUSEX))GetProcAddress(hIL, "GlobalMemoryStatusEx");
if(GMSEx)
{
MEMORYSTATUSEX m;
m.dwLength = sizeof(m);
if(GMSEx(&m))
{
ret = (int)(m.ullAvailPhys>>20);
}
}
else
{
MEMORYSTATUS m;
m.dwLength = sizeof(m);
GlobalMemoryStatus(&m);
ret = (int)(m.dwAvailPhys>>20);
}
#endif
return ret;
}
int getTotalMemory()
{
int ret = 0;
#ifdef WIN32
DWORD v = GetVersion();
DWORD major = (DWORD)(LOBYTE(LOWORD(v)));
DWORD minor = (DWORD)(HIBYTE(LOWORD(v)));
DWORD build;
if (v < 0x80000000) build = (DWORD)(HIWORD(v));
else build = 0;
// because compiler static links the function...
BOOL (__stdcall*GMSEx)(LPMEMORYSTATUSEX) = 0;
HINSTANCE hIL = LoadLibrary(L"kernel32.dll");
GMSEx = (BOOL(__stdcall*)(LPMEMORYSTATUSEX))GetProcAddress(hIL, "GlobalMemoryStatusEx");
if(GMSEx)
{
MEMORYSTATUSEX m;
m.dwLength = sizeof(m);
if(GMSEx(&m))
{
ret = (int)(m.ullTotalPhys>>20) + (int)(m.ullTotalVirtual>>20);
}
}
else
{
MEMORYSTATUS m;
m.dwLength = sizeof(m);
GlobalMemoryStatus(&m);
ret = (int)(m.dwTotalPhys>>20) + (int)(m.dwTotalVirtual>>20);
}
#endif
return ret;
}
int getAvailMemory()
{
int ret = 0;
#ifdef WIN32
DWORD v = GetVersion();
DWORD major = (DWORD)(LOBYTE(LOWORD(v)));
DWORD minor = (DWORD)(HIBYTE(LOWORD(v)));
DWORD build;
if (v < 0x80000000) build = (DWORD)(HIWORD(v));
else build = 0;
// because compiler static links the function...
BOOL (__stdcall*GMSEx)(LPMEMORYSTATUSEX) = 0;
HINSTANCE hIL = LoadLibrary(L"kernel32.dll");
GMSEx = (BOOL(__stdcall*)(LPMEMORYSTATUSEX))GetProcAddress(hIL, "GlobalMemoryStatusEx");
if(GMSEx)
{
MEMORYSTATUSEX m;
m.dwLength = sizeof(m);
if(GMSEx(&m))
{
ret = (int)(m.ullAvailPhys>>20) + (int)(m.ullAvailVirtual>>20);
}
}
else
{
MEMORYSTATUS m;
m.dwLength = sizeof(m);
GlobalMemoryStatus(&m);
ret = (int)(m.dwAvailPhys>>20) + (int)(m.dwAvailVirtual>>20);
}
#endif
return ret;
}
Sadly these things rely heavily on the underlying OS, so there are no platform-independent calls. (Maybe there are some wrapper frameworks, but I don't know of any.)
On Linux you could have a look at the getrusage() function call, on Windows you can use GetProcessMemoryInfo() for RAM Usage. Have also a look at the other functions in the Process Status API of Windows.