Will using PECL to install an extension warn me of any changes it will make?

I'm using some PHP 5.1 code that won't work with a newer version of PHP, but I would like to use the memcache extension with it. I'm not sure if PECL will install additional pack开发者_如何学编程ages, upgrade packages, or remove packages if I use it--and if it does I'd like to have a warning if I run the pecl install memcache command. Will PECL warn me of the specific change it's going to make? Do I have to worry about it upgrading my PHP version? Rudimentary questions, I know, but I'm just trying to be cautious; I've never used it before.

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If you run pecl install memcache I don't believe it'll install any dependencies. It definitely can't upgrade your php install/version, the pecl command only works with extensions and not with the core PHP files.

If you find that you need to install an older version of a PECL extension you can install specific versions (there's a full list of memcache releases here) by specifying the version number e.g. pecl install memcache-2.2.5