Where are the I2C header files?

[henryd]

I am using the cross compiling environment on windows cygwin.
When creating an app for I2C is need header files such as <linux/i2c.h> but they are not a part of the toolset that I downloaded from https://github.com/IanLinsdell/Raspberrypi.
Googling for I2C.h reveals several variants for i2c.h, which one to use?

[joan]

Not sure if it helps with your environment.

On a Pi

sudo apt-get install libi2c-dev

pulls in the development files.

[henryd]

Thanks, I did that.
Can I now just copy the /usr/include/linx from RPi to the /cygwin/opt/cross/xtools/arm-unknow.../include on my windows PC?

[joan]

I don't know, but that is what I'd try.