Difference between $ {CTX} and $ {pagecontext. Request. contextpath}

$ {CTX} and $ {pagecontext. request. contextpath}. It is a newbie and has no experience, but knows $ {pagecontext. request. contextpath} is used to obtain the current root directory, and $ {CTX} can be used to understand the meaning through observation, but does not understand why this is written, after asking an experienced colleague, you will know that both of them mean to get the current root directory. The difference is that $ {CTX} is $ {pagecontext. request. contextpath} is a short version. After verification, it is found that such a paragraph of configuration exists in a project file,<C: setvar = "CTX" value = "$ {pagecontext. Request. contextpath}"/>,It is worth noting that when using $ {CTX}, do not forget to include<C: setvar = "CTX" value = "$ {pagecontext. Request. contextpath}"/>To the current page.