View the dll file content of PHP. how can this problem be solved?

I would like to ask a sad question about viewing the dll file content of PHP. php is an open-source web language and all source code is open and developed in C language, how can I check the source file of php C language? I only know that there are many dll files for more than a year. could you please advise ???, For php source code http://cn.php.net/get/php-5.4.0.tar.gz/from/a to view PHP dll file content
Ask a sad question,
Php is an open-source web language. all source code is open and developed in C language. how can I check the source code of php C language,
For more than a year, I only know that there are many dll files. could you please advise ???

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For php source code
Http://cn.php.net/get/php-5.4.0.tar.gz/from/a/mirror

Go back to the next source code package.
As for the dll extensions you mentioned, you may need to go to different places to view the source code packages they provide. similar to xdebug

Git clone git: // github.com/derickr/xdebug.git

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Discussion

Thank you. there is another question: when I download PHP on the official website, there is an MD5 code next to it. what is the purpose of this code?

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Discussion
Thank you. there is another question: when I download PHP on the official website, there is an MD5 code next to it. what is the purpose of this code?

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There are many such md5 viewing tools. Ask Uncle google.

Discussion

Thank you very much, but what is the verification process? on what official website? after the php file has been downloaded, where can I find the MD5 code corresponding to this file? Sorry for asking so many questions

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Direct md5sum + file name in linux