---

because your php7 does not have an extension installed:
take php7.0 as an example:

sudo apt-get update
sudo apt-get install mcrypt php7.0-mcrypt
sudo apt-get upgrade

if it is apache
sudo service apache2 restart

then check whether the installation is successful:

php-m

find mcrypt

done!

---

Under

windows, it is estimated that it is removed directly from php.ini; it is OK

.

if compiled:

tar zxvf mcrypt-2.6.8.tar.gz / / Note the version number
cd mcrypt-2.6.8
LD_LIBRARY_PATH=/usr/local/lib. / configure
make
make install

PHP compilation added-- with-mcrypt

---

In

phpstudy, different php versions have different PHP directory files, so the file name can tell which version it belongs to. Enter the PHP file directory of the corresponding version, open php.ini and open the corresponding extension, and check whether there is any corresponding extension in the extend extension directory under the current directory. You can download

of window version and linux version of pecl.php.net without downloading it.

the above members have made it very clear under linux