How do you determine the amount of Linux system RAM in C++?

Question

I just wrote the following C++ function to programatically determine how much RAM a system has installed. It works, but it seems to me that there should be a simpler way to

Answer 1

There's no need to use popen(), you can just read the file yourself. Also, if there first line isn't what you're looking for, you'll fail, since head -n1 only reads the first line and then exits. I'm not sure why you're mixing C and C++ I/O like that; it's perfectly OK, but you should probably opt to go all C or all C++. I'd probably do it something like this:

int GetRamInKB(void)
{
    FILE *meminfo = fopen("/proc/meminfo", "r");
    if(meminfo == NULL)
        ... // handle error

    char line[256];
    while(fgets(line, sizeof(line), meminfo))
    {
        int ram;
        if(sscanf(line, "MemTotal: %d kB", &ram) == 1)
        {
            fclose(meminfo);
            return ram;
        }
    }

    // If we got here, then we couldn't find the proper line in the meminfo file:
    // do something appropriate like return an error code, throw an exception, etc.
    fclose(meminfo);
    return -1;
}