以下命令在 makefile 中有什么作用？

Question

$(TARGET): build $(OBJECTS)
        ar rcs $@ $(OBJECTS)
        ranlib $@

What are "ar rcs" and "ranlib"?

Answer 1

ar is used to create libraries (that are archives containing compiled code)

man ar:
ar -- create and maintain library archives
...
-r      Replace or add the specified files to the archive
-c      Whenever an archive is created, an informational message to that effect is written to standard error.  If the -c option is speci-
             fied, ar creates the archive silently.
-s      Write an object-file index into the archive, or update an existing one, even if no other change is made to the archive.  You may
             use this modifier flag either with any operation, or alone.  Running `ar s' on an archive is equivalent to running `ranlib' on
             it.

The first argument is the name of the resulting libraries, the others are the object files to insert in it.

ranlib generates an index to the contents of an archive and stores it in the archive.