The application's Makefile+ file contains an ordinary install target which is run directly when the user does make+ install. The purpose of the install target is to do whatever is necessary to install the program, but in practice this means doing two things:

Here is an example install target. The first four commands are concerned with creating the installation directories. The last five commands are concerned with copying the built program (in this case, a library) to the installation directories. Notice the use of several make+ macros.

install:
        install -d $(DESTDIR)$(libdir)
        install -d $(DESTDIR)$(pkgincludedir)
        install -d $(DESTDIR)$(man3dir)
        install -d $(DESTDIR)$(datadir)/rws/symtabs/

        $(MP_INSTALL_STATIC_LIB) libc2lib.a
        $(MP_INSTALL_DYNAMIC_LIB) libc2lib.so
        install -m 0644 $(HEADERS) $(DESTDIR)$(pkgincludedir)
        install -m 0644 *.3        $(DESTDIR)$(man3dir)
        install -m 0644 *.syms     $(DESTDIR)$(datadir)/rws/symtabs/

$(DESTDIR) must be prefixed onto every install path. Normally it is empty, and so has no effect. However when doing packaged builds (building RPMs for example) it can be used to create a "fake root".

$(libdir), etc., are standard paths for particular directories. For example if the prefix is /usr/local and we are building on Linux, then $(libdir) will expand to /usr/local/lib and $(man3dir) to /usr/local/share/man/man3.