One of the most popular PHP programming languages contains a rich library of functions. Each of them differs in its properties, but due to the large number of operations and similar names, developers often get confused. The questions are raised by the PHP microtime function - what does it do and how does it differ from those similar to it?
Microtime function
In PHP, microtime returns Unix time as a result, accurate to microseconds. Despite the built-in operation in the programming language, it is not capable of working on all systems. In earlier versions of operating systems where the gettimeofday () system call is missing, this function will produce incorrect results.
The microtime () syntax has only one argument - it determines in which type of data the result can be returned. If the value corresponding to true (in English "true") is indicated in parentheses, then instead of numeric data, the function will return a string. In the absence of any parameters (which is zero), false will be indicated (from the English "false"), the time will be returned in the format msec sec. Here, the first number will be the number of microseconds elapsed since the beginning of the current second, and the second is the total time elapsed since 1970, expressed in seconds.
It is necessary to use microtime () in PHP if it is necessary to find out how long it takes to execute a particular piece of code. Most often, this mechanism is used to optimize the program.
Difference from time
As a similar function with microtime, PHP has a simpler one - time. Unlike its more accurate "sister", the result of using the time () function is the number of seconds that have passed since the beginning of the Unix era, that is, from January 1, 1970, 00:00:00 GMT. Using time (), you can achieve the time difference between two points of the program, however, with less accuracy.
If you need to get the system time, then you should use the date () function. If you need to get the maximum accuracy of the difference, it is best to choose the PHP function - microtime.