read sensor information on linux

sensors.cpp

#include <cstdio>
#include <cstdlib>
#include <string>

#include <sensors/sensors.h>
#include <sensors/error.h>

/**
 * Reads informations of all sensors and print them, a little bit rawish
 *
 * Compile it with `g++ sensors_test.cpp -o sensors_test -lsensors --std=c++17 -Wall` 
 *
 * Since libsensors is linux-specific, it will only work on Linux
 */

int main(int argc, char* argv[]) 
{
	if (sensors_init(nullptr)) {
		puts("Error");
		return 1;
	}

	/**
	 * This library is organized in the following way
	 *  - Chips
	 *     | - Features, like "groups" of sensors
	 *     |     | - Subfeatures, the sensors themselves
	 */

	int i = 0;
	for(auto* chip = sensors_get_detected_chips(nullptr, &i);
	    chip != nullptr;
	    chip = sensors_get_detected_chips(nullptr, &i))
	{
		char orig_name[256] = {};
		if (auto e = sensors_snprintf_chip_name(orig_name, 255, chip); e < 0) {
			printf("Error while getting chip name: %s\n", sensors_strerror(e));
			continue;
		}

		printf("%d: %s\n", i+1, orig_name);

		int feati = 0;
		for (auto* feat = sensors_get_features(chip, &feati); feat != nullptr; 
			feat = sensors_get_features(chip, &feati))
		{
			// get feature type
			const char* ftype;
			switch (feat->type) {
				case SENSORS_FEATURE_IN: ftype = "in"; break;
				case SENSORS_FEATURE_FAN: ftype = "fan"; break;
				case SENSORS_FEATURE_TEMP: ftype = "temperature"; break;
				case SENSORS_FEATURE_POWER: ftype = "power"; break;
				case SENSORS_FEATURE_ENERGY: ftype = "energy"; break;
				case SENSORS_FEATURE_CURR: ftype = "current"; break;
				case SENSORS_FEATURE_HUMIDITY: ftype = "humidity"; break;
	
				// there are more types, but I will not show them
				default: ftype = "other"; break;
			}



			printf("\tfeature %s, number %d, type %02x (%s)\n", 
			       feat->name, feat->number, feat->type, ftype);

			int sfeati = 0;
			for (auto* sfeat = sensors_get_all_subfeatures(chip, feat, &sfeati); sfeat != nullptr; 
			    sfeat = sensors_get_all_subfeatures(chip, feat, &sfeati))
			{
				/// get flags
				std::string flagstr = "";
				if (sfeat->flags & SENSORS_MODE_R)
					flagstr += " readable";
				if (sfeat->flags & SENSORS_MODE_W)
					flagstr += " writable";
				if (sfeat->flags & SENSORS_COMPUTE_MAPPING)
					flagstr += " affected-by-main-feature";

				// write sensor data
				printf("\t\tsubfeature %s, number %d, type %04x, mapping %08x, flags %02x (%s )\n", 
			       		sfeat->name, sfeat->number, sfeat->type, sfeat->mapping, sfeat->flags, flagstr.c_str());

				double val = 0.0;
				if (auto e = sensors_get_value(chip, sfeat->number, &val); e < 0) {
					printf("\t\t\terror '%s' while getting value", sensors_strerror(e));
				} else {
					printf("\t\t\tvalue %.2f", val);
				}

				puts(")");

			}
			

		}
	}


	sensors_cleanup();
	return 0;
}