1.Uncaught Error: Call to undefined function mb_strlen();
When errors occur, indicating we have no install mbstring extension;
2. Enter the PHP install directory
cd /temp001/php-7.1.0/ext/mbstring
3. start the phpize (/usr/local/bin/phpize or/usr/local/PhP7-abel001/bin/phpize) command to install PHP extensions
4../configure–with-php-config=/usr/local/PhP7-abel001/bin/php-config according to your actual installation directory
5. compile make && make install
6. mbstring.so is generated in the/usr/local/PhP7-abel001/lib/php/extensions/no-debug-non-ZTS-20160303/directory;
7.echo ‘extension=mbstring.so’ >>/usr/local/PhP7-abel001/lib/php.ini enable mbstring extension
8.nginx-s reload, killall PHP-fpm./php-fpm reloaded PHP-fpm
9.php-m command to see which extensions have been enabled; PHP–ini can see the PHP configuration information
Thus mbstring extension has been installed successfully!