What is time(NULL) in C?

Question

I learning about some basic C functions and have encountered time(NULL) in some manuals.

What exactly does this mean?

Answer 1

The call to time(NULL) returns the current calendar time (seconds since Jan 1, 1970). See this reference for details. Ordinarily, if you pass in a pointer to a time_t variable, that pointer variable will point to the current time.