在编译 sensor.c出错
pi@berryboot ~ $ gcc -o sensor sensor.c
/tmp/cc4K2u7Z.o: In function `dht11_read_val':
sensor.c.text+0x84): undefined reference to `delay'
sensor.c.text+0x2b0): undefined reference to `pinMode'
sensor.c.text+0x2b4): undefined reference to `digitalWrite'
sensor.c.text+0x2b8): undefined reference to `delayMicroseconds'
sensor.c.text+0x2bc): undefined reference to `digitalRead'
/tmp/cc4K2u7Z.o: In function `main':
sensor.c.text+0x2d4): undefined reference to `wiringPiSetup'
sensor.c.text+0x2f4): undefined reference to `delay'
collect2: ld returned 1 exit status