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This article mainly introduces the php common variable types of what is the relevant knowledge, the content is detailed and easy to understand, the operation is simple and fast, has a certain reference value, I believe you will get something after reading this php common variable type article, let's take a look at it.

1. Integer and floating point

For integers and floating-point types, because of their small footprint, the values of integers stored directly in zval are stored in lval, while floating-point values are stored in dval.

Typedef union _ zend_value {zend_long lval; / * integer * / double dval; / * floating point * /...}

2. String

A new string structure is defined in PHP 7. The structure is as follows:

Gc: variable reference information, which is the structure of all variable types that use reference counting.

H: hash value, which is used when calculating the index in the array. (this operation is said to improve the performance of PHP7 by 5%)

Len: string length, which is used to ensure binary security

Val: string content, variable length struct, memory array applied for according to len length when allocating

Struct _ zend_string {zend_refcounted_h; zend_ulong h; / * hash value * / size_t len;char val [1];}; this is the end of the article on "what are common variable types in php". Thank you for reading! I believe you all have a certain understanding of the knowledge of "what are the common variable types of php". If you want to learn more, you are welcome to follow the industry information channel.

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