Is it possible to use Bluetooth to connect two EV3 bricks using RobotC? For example to send a numeric value from one to the other?
According to the online documentation, Bluetooth commands are supported for NXT but not for EV3.

On the other hand RobotC is supporting Bluetooth upload/debugging.  This means that it is accessible.  My first instinct would be to look at how RobotC did it (if the code is available).  My second instinct would be to find if somebody already hacked the EV3 brick using C code.