Can't access GPIO pins directly from C++ with wiringPi

Question

I'm trying to access the GPIO pins of a Raspberry Pi 3 model B directly from c++.

This code works fine with wiringPiSetup() and wiringPiSetupGpio() but I want to access the GPIO registers directly and wiringPySetupPhys() doesn't work this way. I tried BCM and wiringPi pin numbering too.

What am I doing wrong? Are there any other way for fast GPIO access in c++?

#include <wiringPi.h>

int main(){
    wiringPiSetupPhys();
    pinMode(18,OUTPUT);
    digitalWrite(18,HIGH);
}

Answer 1

You cannot mix "direct register access" with code using GPIO libraries. You have to select one method and stick to it fom beginning do end, no matter how painful it is.

A good example of direct register access, from the author of pigpio: http://abyz.me.uk/rpi/pigpio/code/minimal_gpio.zip

I hope you now understand why pigpio and WiringPi exist in the first place. There is a lot of boilerplate code hidden by them.