分类: PHP专题

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


输出:

PHP

输出:

PHP
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