How to read a Raspberry PI temperature in C code
Reading the temperature of a Raspberry PI can be done in a couple of ways. This command:
vcgencmd measure_tempOutputs something like temp=32.7’C. My 3B+ PI has heatsinks and a cooling fan so runs cool. Even with asteroids it only peaked at 50.5C. Well below the throtle back temperature of 85C.
Another way (I suspect they are the same) is to do
cat /sys/class/thermal/thermal_zone0/tempWhich outputs values like 32705. Just divide by 1000 to get the temperature in Celsius.
But how do we do it in code? Well I’ve tested this code below and it seems to work.
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
int main(void) {
char buffer[10];
char * end;
FILE * temp = fopen("/sys/class/thermal/thermal_zone0/temp","rt");
int numread = fread(buffer,10,1,temp);
fclose(temp);
printf("Temp = %5.2fC\n",strtol(buffer,&end,10)/1000.0);
}It reads the device as a string then converts to a long using strtol and divides that by 1000 then prints it. Output is something like:
Temp (C) = 34.88C
Now it just needs combined with the code to detect that it’s running on a Pi and you’re good.
Normally I wouldn’t mention it, as there’s nothing really outstanding about the update (accessibility improvements, Timeline view, Better quick open for files etc.) You can read all about it 
Silly me completely forgot that Raspberry Pis have a different CPU architecture compared to my PC. You just get used to something working on Linux and it was only after copying and it didn’t run that I realised my mistake. So I now have to recompile Asteroids (from 
Microsoft don’t do an official version for Raspberry-Pi or other ARM boards. However I discovered that a developer called Jay Rodgers has taken their source code (VS Code is open source) and you can get a version 
Clang is very easy to install. Open a terminal and issue this command:
Confession, I can program in C++ though I’m a bit rusty and my C++ knowledge stops short of creating template classes but I can use them. But given that probably most games these days are programmed in C++ why is this site about C?
My secret: is I use a piece of software called 
If you have a bit of nesting and you want to make sure your braces match up, Visual Studio code (VSC) can help you with that.
