How Can I Get Available System Memory in a Platform-Independent Way Using C ?

Getting Available Memory in a Platform-Independent Way C /g

In order to allocate buffers to match system memory availability while staying within allowable limits, it's essential to determine the available memory. This knowledge enables dynamic allocation decisions without exceeding the system's capacity. The memory status (whether virtual or physical) may not have significant implications, but obtaining this information is crucial for cross-platform compatibility across Windows, OS X, Linux, and AIX.

For UNIX-like operating systems, the sysconf function provides access to system memory information. By retrieving the number of available pages (_SC_PHYS_PAGES) and the page size (_SC_PAGE_SIZE), it's possible to calculate the total system memory:

#include <unistd.h>

unsigned long long getTotalSystemMemory()
{
    long pages = sysconf(_SC_PHYS_PAGES);
    long page_size = sysconf(_SC_PAGE_SIZE);
    return pages * page_size;
}

For Windows, GlobalMemoryStatusEx offers a direct way to obtain system memory statistics. The returned MEMORYSTATUSEX structure contains the physical memory details, which can be used to compute the total system memory:

#include <windows.h>

unsigned long long getTotalSystemMemory()
{
    MEMORYSTATUSEX status;
    status.dwLength = sizeof(status);
    GlobalMemoryStatusEx(&amp;status);
    return status.ullTotalPhys;
}

By combining these platform-specific implementations via #ifdefs or macros, it's possible to determine the available memory across multiple systems and make informed buffer allocation decisions accordingly.

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