Question

I’m reading linux kernel code and I encounter something like the following:

typedef void (* gps_location_callback)(GpsLocation* location）

then later it can be used like:

gps_location_callback location_cb;

Can somebody tell me what does that typedef mean? I never saw something like this before..
Thanks!

Answer 1

This is a function pointer. Variables of this type point to a function whose signature is void (GpsLocation*):

void foo(GpsLocation *);

gps_location_callback f = foo;

// now use f(p) etc

Without the typedef you’d have to write:

void (*f)(GpsLocation *) = foo;