PHP 7-期望 - 芒果文档

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📜 PHP 7-期望

📅 最后修改于: 2020-10-21 04:58:32 🧑 作者: Mango

期望是对较早的assert（）函数的向后兼容增强。期望允许在生产代码中使用零成本的断言，并提供断言失败时引发自定义异常的功能。 assert（）现在是一种语言构造，其中第一个参数是与要测试的字符串或布尔值相比的表达式。

assert（）的配置指令

Directive	Default value	Possible values
zend.assertions	1	1 − generate and execute code (development mode) 0 − generate code but jump around it at runtime -1 − do not generate code (production mode)
assert.exception	0	1 − throw, when the assertion fails, either by throwing the object provided as the exception or by throwing a new AssertionError object if exception was not provided. 0 − use or generate a Throwable as described above, but only generates a warning based on that object rather than throwing it (compatible with PHP 5 behaviour)

Directive

Default value

Possible values

zend.assertions

1 − generate and execute code (development mode)

0 − generate code but jump around it at runtime

-1 − do not generate code (production mode)

assert.exception

1 − throw, when the assertion fails, either by throwing the object provided as the exception or by throwing a new AssertionError object if exception was not provided.

0 − use or generate a Throwable as described above, but only generates a warning based on that object rather than throwing it (compatible with PHP 5 behaviour)

参量

断言-断言。在PHP 5中，它必须是要评估的字符串或要测试的布尔值。在PHP 7中，这也可以是任何返回值的表达式，该表达式将被执行，并且结果用于指示断言是成功还是失败。
description-断言失败时将包含在失败消息中的可选描述。
exception-在PHP 7中，第二个参数可以是Throwable对象，而不是描述性字符串，在这种情况下，如果断言失败并且启用了assert.exception配置指令，则这是将要抛出的对象。

返回值

FALSE如果断言是假的，否则返回true。

例

它产生以下浏览器输出-

Fatal error: Uncaught CustomError: Custom Error Message! in...