1.6. qmake, Project Files, and Makefile

C++ applications are generally composed of many source files, header files, and external libraries. During the normal course of project development, source files and libraries get added, changed, or removed. To build an executable that reflects the current state of the project, such changes require all affected files to be compiled and the resulting object files to be properly linked. This changing-rebuilding process typically happens many times.

Keeping track of all the parts of such a project requires a mechanism that precisely specifies the input files involved, the tools needed to build, the intermediate targets and their dependencies, and the final executable target.