Raspberry Pi/WiringPi simple example

blink.c

#include <wiringPi.h>

const int ledPin = 18;

int main(void)
{
    wiringPiSetupGpio();

    pinMode(ledPin, OUTPUT);

    for (;;)
    {
        digitalWrite(ledPin, HIGH);
        delay(500);
        digitalWrite(ledPin, LOW);
        delay(500); 
    }

    return 0;
}

Makefile

LDLIBS=-lwiringPi

blink: blink.c

run: blink
	sudo ./blink
.PHONY: run

clean:
	$(RM) blink
.PHONY: clean

A GForth port of this example is available here: https://gist.github.com/kristopherjohnson/e7d3f7547eb5e1c65aff