PHP pack() function
definition and usage
The pack() function packs data into a binary string.
syntax
pack(format,args+)
| parameter | description |
|---|---|
| format | required. Specifies the format used when wrapping data. |
| args+ | optional. Specifies one or more parameters to be wrapped. |
format 参数的可能值：
- a - NUL-padded string
- A - SPACE-padded string
- h - Hex string, low nibble first
- H - Hex string, high nibble first
- c - signed char
- C - unsigned char
- s - signed short (always 16 bit, machine byte order)
- S - unsigned short (always 16 bit, machine byte order)
- n - unsigned short (always 16 bit, big endian byte order)
- v - unsigned short (always 16 bit, little endian byte order)
- i - signed integer (machine dependent size and byte order)
- I - unsigned integer (machine dependent size and byte order)
- l - signed long (always 32 bit, machine byte order)
- L - unsigned long (always 32 bit, machine byte order)
- N - unsigned long (always 32 bit, big endian byte order)
- V - unsigned long (always 32 bit, little endian byte order)
- f - float (machine dependent size and representation)
- d - double (machine dependent size and representation)
- x - NUL byte
- X - Back up one byte
- @ - NUL-fill to absolute position
实例
例子 1
<?php
echo pack("C3",80,72,80);
?>
输出：
PHP
例子 2
<?php
echo pack("C*",80,72,80);
?>
输出：
PHP
