Gauss中除了.src,.g,.fmt文件以外，其他的文件名全凭个人随意起。

If there a large numbe of global matrices and strings used in procedure definitions, it is better to place all the ‘external’ commands in a separate file with a file name having the ‘.ext’ extension and all the ‘declare’ commands in another file with a file name having the ‘.dec’ extension. When the corresponding procedure is to be compiled, we can ‘include’ the ‘.ext’ file before the procedure.The ‘.dec’ file needs not be ‘included’. It can be recorded in a library file so that they can be accessed just like the procedure definitions are.

You may have several procedures in different files that reference the same global variable. By placing an external statement at the top of each file, you can let the compiler know if the symbol is a matrix, string, or procedure. If the symbol is listed and strongly typed in an active library, no external statement is needed.