Function to measure available memory on Linux, can be easily adopted to get any value from /proc/meminfo

memavailable.cpp

#include <string.h>
#include <cstdlib>

bool get_memavailable_from_meminfo(size_t &memavailable)
{
    const int LINE_LEN = 512;
    char str[LINE_LEN];

    FILE *fp = fopen("/proc/meminfo","rt");
    if (fp == NULL) {
//		perror("Cannot open /proc/meminfo");
        return false;
    }

    while (true) {
        if (fgets(str, LINE_LEN, fp) == NULL) {
            fclose(fp);
            return false;
        }
        if (!strncmp(str, "MemAvailable:", strlen("MemAvailable:"))) {
            break;
        }
    }

    memavailable = (size_t) atoll(str + strlen("MemAvailable:")) * 1024; // Convert kilobytes to bytes

    fclose(fp);
    return true;
}