Makefiles contain five kinds of things: explicit rules, implicit rules, variable definitions, directives, and comments. Rules, variables, and directives are described at length in later chapters.
objectsas a list of all object files (see Variables Make Makefiles Simpler).
maketo do something special while reading the makefile. These include:
#, escape it with a backslash (e.g.,
\#). Comments may appear on any line in the makefile, although they are treated specially in certain situations.
You cannot use comments within variable references or function calls:
any instance of
# will be treated literally (rather than as the
start of a comment) inside a variable reference or function call.
Comments within a recipe are passed to the shell, just as with any other recipe text. The shell decides how to interpret it: whether or not this is a comment is up to the shell.
define directive, comments are not ignored during the
definition of the variable, but rather kept intact in the value of the
variable. When the variable is expanded they will either be treated
make comments or as recipe text, depending on the context in
which the variable is evaluated.