Return values
The function returns the value of the high precision timer. The time is measured in seconds, and is
returned as a double precision floating point value.

Description
The function returns the state of a high precision timer. Unless the timer has been set by the
glfwSetTime function, the time is measured as the number of seconds that have passed since glfwInit
was called.

Notes
The resolution of the timer depends on which system the program is running on. The worst case
resolution is somewhere in the order of 10 ms, while for most systems the resolution should be better
than 1 μs.