I found when I use USIWire from an Arduino Library ( a .cpp file, not the main sketch file, like a .ino file), then compiling that library, I get USIWire.h:58:5: error: 'size_t' does not name a type size_t write(uint8_t).
So it looks like just including the "stddef.h" here in the USIWire.h header fixes this.
I found when I use USIWire from an Arduino Library ( a .cpp file, not the main sketch file, like a .ino file), then compiling that library, I get
USIWire.h:58:5: error: 'size_t' does not name a type size_t write(uint8_t)
.So it looks like just including the "stddef.h" here in the USIWire.h header fixes this.
I use Arduino IDE 1.8.1 on MacOS.