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李清波 2021-06-17 PHP函数 1808 复制当前网址

pack



PHP pack() 函数

定义和用法

pack() 函数把数据装入一个二进制字符串。


语法

pack(format,args+)


参数描述
format必需。规定在包装数据时所使用的格式。
args+可选。规定被包装的一个或多个参数。


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


例子

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


文章来源:http://liqingbo.com/blog-936.html

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