wire.h - it's not listed in my installed libraries

Projects Programming
1

Hi folks,

Does wire.h come with the IDE? I'm able to include it with my sketches but I don't ever remember adding the library. Also, it's not on the list of installed libraries. What am I missing?

Happy holidays,

Tony

2

The Wire (uppercase W) library is included with the IDE

Take a look in C:\Program Files (x86)\Arduino\hardware\arduino\avr\libraries\Wire\src\

3

Wire is what's known as a "platform bundled library". Some libraries are very architecture-specific, so that the code is very much written for a certain family of microcontrollers. In the case of libraries providing essential capabilities, such as Wire, it makes the most sense to provide the library along with the boards platform that adds Arduino support for that architecture. The reason you won't find the platform bundled libraries listed in Arduino Library manager is because these libraries are distributed along with the boards platforms and it wouldn't really make sense to distribute the libraries by themselves (because you will often need to have multiple versions installed at the same time).

Each boards platform bundles its own version of the Wire library. The path UKHeliBob provided is the version bundled with the copy of the Arduino AVR Boards platform that comes with the Arduino IDE. But if you're using a board of a different architecture, such as the MKR Zero (Arduino SAMD Boards platform), or the Nano Every (Arduino megaAVR Boards platform), then that library won't be used and the Wire library in use will be in a different location. Because all the libraries provide a compatible, consistent API, it will seem like you're using the same library for all your boards, but if you peek at the source code, you might find it's significantly different from one library to another.

An easy way to find the location of the Wire library for the board you have currently selected in the IDE is to open one of the Wire library's example sketches, then use the Sketch > Show sketch folder menu to open the example sketch's folder. After that, you can navigate up a couple folder levels to get to the root of the repository, under which will be the source code.