Introduction
In this article I describe the PHP Miscellaneous functions sleep, time_nanosleep, time_sleep_until, uniqid, unpack and usleep. To learn some other FileSystem functions, go to:
- Misc Function in PHP: Part 1
- Misc Function in PHP: Part 2
- Misc Function in PHP: Part 3
PHP sleep() Function
The PHP Miscellaneous sleep function delays execution of the current script for a specified number of seconds and it returns zero on success or false on error.
Syntax
Parameter in sleep function
The parameter of the function is:
Parameter |
Description |
seconds |
It specifies the number of seconds to delay the script. |
Example
An example of the function is:
<?php
print_r(date('h:i:s'));
sleep(10);
echo "</br>";
print_r(date('h:i:s')); // it prints after 10 seconds time.
?>
Output
PHP time_nanosleep() Function
The PHP Miscellaneous time_nanosleep function delays execution for a specified number of seconds and nanoseconds and this function returns true on success or false on failure.
Syntax
time_nanosleep(seconds,nanoseconds) |
Parameter in time_nanosleep function
The parameters of the function are:
Parameter |
Description |
seconds |
It specifies the number of seconds to delay the script. |
nanoseconds |
It specifies the number of nanoseconds to delay the script. |
Example
An example of the function is:
<?php
echo time_nanosleep(2,20000)? 'true':'false';
echo "</br>";
if(time_nanosleep(0,50000000)===true)
{
echo "Slept for a half of a second\n";
}
else
{
echo "Something went wrong!";
}
?>
Output
PHP time_sleep_until() Function
The PHP Miscellaneous time_sleep_until function puts the script asleep until the specified time and this function returns true on success or false on failure.
Syntax
time_sleep_until(timestamp) |
Example
An example of the function is:
<?php
var_dump(time_sleep_until(time()+10));
?>
Output
PHP uniqid() Function
The PHP Miscellaneous uniqid function generates a unique id based on the micro time and this function returns the unique identifier, as a string.
Syntax
uniqid(prefix,more_entropy) |
Parameter in uniqid function
The parameters of the function are:
Parameter |
Description |
prefix |
It specifies the prefix of the unique id. |
more_entropy |
It specifies more entropy at the end of the return value. |
Example
An example of the function is:
<?php
echo uniqid();
?>
Output
PHP unpack() Function
The PHP Miscellaneous unpack function unpacks data from a binary string and this function returns an associative array containing unpacked elements of the binary string.
Syntax
Parameter in unpack function
The parameters of the function are:
Parameter |
Description |
format |
It specifies the format to use when unpacking data and its possible values are:
- a - It specifies NUL-padded string.
- A - It specifies SPACE-padded string.
- c - It specifies signed char.
- C - It specifies unsigned char.
- d - It specifies double (machine dependent size and representation).
- f - It specifies float (machine dependent size and representation).
- h - It specifies hex string, low nibble first.
- H - It specifies hex string, high nibble first.
- i - signed integer (machine dependent size and byte order).
- I - It specifies unsigned integer (machine dependent size and byte order).
- l - It specifies signed long (always 32 bit, machine byte order).
- L - It specifies unsigned long (always 32 bit, machine byte order).
- n - It specifies unsigned short (always 16 bit, big endian byte order).
- N - It specifies unsigned long (always 32 bit, big endian byte order).
- s - It specifies signed short (always 16 bit, machine byte order).
- S - It specifies unsigned short (always 16 bit, machine byte order).
- v - It specifies unsigned short (always 16 bit, little endian byte order).
- V - It specifies unsigned long (always 32 bit, little endian byte order).
- x - It specifies NUL byte.
- X - It specifies Back up one byte.
- @ - It specifies NUL-fill to absolute position.
|
data |
It specifies the binary data to be unpacked. |
Example
An example of the function is:
<?php
echo "<pre>";
$content= "PHP";
print_r( unpack("C*",$content));
?>
Output
PHP usleep() Function
The PHP Miscellaneous usleep function delays execution in microseconds and this function returns no value.
Syntax
Parameter in usleep function
The parameter of the function is:
Parameter |
Description |
microseconds |
It specifies the number of micro seconds to delay the script. |
Example
An example of the function is:
<?php
print_r(date('h:i:s'));
usleep(10000000);
echo "</br>";
print_r(date('h:i:s')); // it prints after 10 seconds time.
?>
Output