The ^ is already taken in context of "C lambdas" though (hoping that if C ever gets lambdas it will simply adopt clang blocks instead of a C++ like syntax):
IMO it would've been better (read, cleaner) to merge lambdas and function pointers into a single language construct. Throw in the partial application too and we'd be have a natively supported concept of a "callable" instance -
void foo(int tick);
void bar(int tick, int tock);
void do_something( void (* progress)(int tick) );
do_something( foo );
do_something( bar(,1) );
do_something( void (int tick) { /* lambda */ } );