What constant represents “never” for an NSTimeInterval?
问题 NSTimeInterval is a double , thus it cannot take a nil , and 0 represents something that should happen immediately. Is there a constant that means "never"... or an astronomically huge value, or should I use -1? 回答1: As suggested by s.bandara, use a very large number to treat a time interval as "infinite" or "never". DBL_MAX is the largest value a double can hold. This macro is declared in float.h : #define DBL_MAX (9.999999999999999e999) 来源: https://stackoverflow.com/questions/28200472/what