Code blocks multi-file joint compilation

???? Code: blocks is an IDE that is often said to be very powerful. Although it is often used in the past, it has never used a high degree of functionality, and has never used it to write engineering things, to put it simply, more than one source file is added with other non-standard header files. Today, I want to test the syntax of multiple files. The result of CB is unfortunately not compiled, when a function in another source file is called in the main function, no reference is prompted. After several minutes, the cause is finally found:

In the manager window (that is, the List window of files such as source files and header files), right-click the source file of the defined function and a menu is displayed. Select properties and a dialog box appears.

???? Select the second Tag: Build, select both the check boxes debug and release in build, and then click OK to compile normally. Although I don't know if it is a correct solution, can I finally compile the program ~?

During the use of the extern function, an undefined error occurs,

Check the build log and find that only main. C,

Suddenly, belongs in targets: I did not select either of them, so the compilation failed,

You only need to select the files you want to add.

Code blocks multi-file joint compilation