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In PHP development, mbstring extension is a part of what we can't avoid when dealing with multibyte strings. mb_get_info() is a function used to obtain information about the current multibyte configuration environment. However, many developers may fall into some common misunderstandings when using it to process Chinese strings. This article will take you to understand these pitfalls and help you avoid making mistakes in your project.
mb_get_info() is not a function used to "process strings". Its main function is to obtain the configuration information of the current mbstring environment . Many beginners mistakenly think that this function can detect whether a string is Chinese, whether the encoding is correct, and can even use it directly to perform string operations. In fact, it just returns information such as the current language settings, encoding settings, internal encoding, etc.
<?php
print_r(mb_get_info());
?>
The output content is similar to:
Array
(
[internal_encoding] => UTF-8
[http_output] => UTF-8
[http_input] => pass
[func_overload] => 0
...
)
These are environmental information and cannot do anything about the Chinese string itself.
When viewing information using mb_get_info() , if you find that internal_encoding is not UTF-8 , you have to be careful. Because when dealing with Chinese strings, UTF-8 is the most general and safest encoding method. If you do not set or set incorrectly, it may cause subsequent functions such as mb_strlen() , mb_substr() to process Chinese errors, garbled or truncated exceptions.
Correct setting method:
<?php
mb_internal_encoding("UTF-8");
You can also check if the current settings are correct by mb_get_info('internal_encoding') :
<?php
echo "Current internal encoding：" . mb_get_info("internal_encoding");
?>
The func_overload field returned by mb_get_info() indicates whether the function overloading is enabled in PHP. If you enable (value greater than 0), native functions such as strlen() and substr() may be overloaded by mbstring . This can lead to inconsistent behavior in some cases.
For example, the following code:
<?php
$str = "Chinese test";
echo strlen($str); // if func_overload Open，It may be calculated by number of characters rather than bytes
?>
In some systems, 12 will be returned (3 bytes per Chinese), instead of the 4 you expect (number of characters), which can cause compatibility issues.
It is recommended to use explicit mb_strlen() instead of native functions and turn off func_overload , or always assume in the code that it is closed.
Many people will combine mbstring and URL operations, such as splicing URLs with Chinese parameters. When using Chinese strings for urlencode() operation, if the encoding is not set to UTF-8 , you may get the wrong URL encoding.
Example:
<?php
mb_internal_encoding("UTF-8");
$name = "Zhang San";
$url = "https://gitbox.net/search?name=" . urlencode($name);
echo $url;
?>
If not set to UTF-8, urlencode() may output garbled or incorrectly encoded strings, causing the link to be invalid.
mb_get_info() is a useful diagnostic tool, but it does not handle strings by itself. It is more used to help developers understand and confirm whether the current PHP multibyte environment is configured correctly. When processing Chinese strings, pay special attention to encoding settings, the impact of function overloading, and encoding compatibility when combined with other functions such as URLs.
Avoiding the above misunderstandings can make your PHP project more stable and efficient when dealing with Chinese. If you are debugging character problems in a local environment or production environment, you might as well use mb_get_info() more, it can provide a lot of valuable information!
