Home Backend Development PHP Tutorial 为何function_exists 总返回faulse

为何function_exists 总返回faulse

Jun 13, 2016 am 10:35 AM
echo exists function include php

为什么function_exists 总返回faulse?
如题。函数写在另一个php文件中,调用function_exists之前,用include包含进来。
可是就是返回false,想不明白。

  谢谢各位

------解决方案--------------------
php文件名一致吗?
函数名称一致吗?
大小写一样吗?
------解决方案--------------------
你把那个函数放到你判断的这个页面上来
如下:
function aa(){
return 'bb';
}
if (function_exists(aa))
{
echo 'yes';
}else{
echo 'no';
}
这种情况我测是输出yes的,没问题的,
另外,也可以直接在你这个页面去调用那个函数,看会不会出错,如果不出错,但用function_exists判断时却不对的话,可能是你的PHP版本或是环境的问题吧,一般不会出问题的。。
------解决方案--------------------
请帖出示例文件

应该是嵌入文件中出错了
------解决方案--------------------
看看一楼说的,要么就是你包含时出了问题,我用include,require测试都没问题。

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