PATH_RAPL_SYSFS
fprintf(outf, "%s: %s", domain_path + strlen(PATH_RAPL_SYSFS) + 1, str);
if ((dir = opendir(PATH_RAPL_SYSFS)) == NULL) {
warn("open %s failed", PATH_RAPL_SYSFS);
snprintf(path, PATH_MAX, "%s/%s/name", PATH_RAPL_SYSFS, entry->d_name);
snprintf(path, PATH_MAX, "%s/%s", PATH_RAPL_SYSFS, entry->d_name);
snprintf(path, PATH_MAX, "%s/%s/%s", PATH_RAPL_SYSFS, entry->d_name, centry->d_name);