These functions control the way make runs. Generally, they are used to provide information to the user of the makefile or to cause make to stop if some sort of environmental error is detected.
Generates a fatal error where the message is
text. Note that
the error is generated whenever this function is evaluated. So, if
you put it inside a recipe or on the right side of a recursive
variable assignment, it won’t be evaluated until later. The
text will be expanded before the error is generated.
ifdef ERROR1 $(error error is $(ERROR1)) endif
will generate a fatal error during the read of the makefile if the
ERROR1 is defined. Or,
ERR = $(error found an error!) .PHONY: err err: ; $(ERR)
will generate a fatal error while
make is running, if the
err target is invoked.
This function works similarly to the
error function, above,
make doesn’t exit. Instead,
text is expanded
and the resulting message is displayed, but processing of the makefile
The result of the expansion of this function is the empty string.
This function does nothing more than print its (expanded) argument(s) to standard output. No makefile name or line number is added. The result of the expansion of this function is the empty string.