When I run composer install on command promp, there exist error like this :
Problem 1
- Installation request for laravel/horizon v1.1.0 -> satisfiable by laravel/horizon[v1.1.0].
- laravel/horizon v1.1.0 requires ext-pcntl * -> the requested PHP extension pcntl is missing from your system.
To enable extensions, verify that they are enabled in your .ini files:
- C:\xampp-7.1\php\php.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
我如何解决这个错误？