今天在linux上面智障一般搞了好久，本来想安装个swoole的，然后用 php -m 的命令想看下安装的PHP扩展库，发现有的扩展库有的可以出来，有的加载失败，
加载失败的错误类型：
PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/memcached.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/memcached.so: undefined symbol: zend_new_interned_string in Unknown on line 0
如下：
[root@pys /]# php -m PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/memcached.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/memcached.so: undefined symbol: zend_new_interned_string in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/swoole.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/swoole.so: undefined symbol: zend_new_interned_string in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/redis.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/redis.so: undefined symbol: zend_new_interned_string in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/curl.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/curl.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/fileinfo.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/fileinfo.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/gd.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/gd.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/json.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/json.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/phar.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/phar.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/zip.so' - /usr/local/php7/lib/php/extensions/no-debug-non-zts-20151012/zip.so: cannot open shared object file: No such file or directory in Unknown on line 0 [PHP Modules] bz2 calendar Core ctype date ereg exif filter ftp gettext gmp
上面的意思是 ：找不到扩展库的路径； 这是为什么尼？不是有的扩展库也可以出来吗？
然后我是百度上找各种答案，并不能解决我的问题，最后自己发现问题所在：
因为我并没有为所有的扩展库加了快捷链接，以为在哪里只要用 php -m 的命令就可以查看所有的扩展库。
其实是要：/usr/local/php7/bin/php -m 这个命令才可以，我的是PHP7.0版本的，其他版本自己换下这个路径就好。
如此，就可以看到所有的扩展库了：
[root@pys bin]# /usr/local/php7/bin/php -m [PHP Modules] bcmath Core ctype curl date dom fileinfo filter ftp gd gettext hash iconv json libxml mbstring mcrypt memcached mysqli mysqlnd openssl pcntl pcre PDO pdo_mysql pdo_sqlite Phar posix redis Reflection session shmop SimpleXML soap sockets SPL sqlite3 standard swoole sysvsem tokenizer xml xmlreader xmlrpc xmlwriter zip zlib [Zend Modules]