Linux versus Particle-agent

The Archive Raspberry Pi
7

Re the simple Particle-RPi test program: here’s my latest try (eliminating most C++ crap).

#include 
#include 

#define SAFE_UID 1000 // i.e., the "pi" user built into RPi Linux
#define MY_PATH "/home/pi"
char Rstr[100];
int Ct = 0;

void setup() {
    Particle.variable("dhpi1v", Rstr, STRING);
    Particle.function("dhpi1f", pifunc);
}

void loop() {
    delay(10); // kludge to keep the empty loop from being a cpu hog
}

int pifunc(String cmd) {
    int arg = cmd.toInt();
    char file[100];
    FILE *fp;
    
    ++Ct;
    sprintf(Rstr, "Call count = %d, Arg = %d\n", Ct, arg);
    sprintf(file, "%s/pi_out.txt", MY_PATH);
    fp = fopen(file, "w");
    fputs(Rstr, fp);
    fclose(fp);
    chown(file, SAFE_UID, SAFE_UID); // Works.
    return Ct;
}