makefileocamlgnu-makeocamlbuild

OCaml Makefile: No Rule to Make Target

I'm following this OCamlbuild example, and accordingly have created the Makefile below:

OCB_FLAGS = -use-ocamlfind -I src -I lib
OCB = ocamlbuild $(OCB_FLAGS)

check: ocamlfind query core async
clean: $(OCB) -clean
byte: $(OCB) main.byte
native: $(OCB) main.native

.PHONY: check clean byte native

The root directory contains two sub-directories, src and lib. The src sub-directory contains the file main.ml.

When I execute any of the targets, e.g. make clean, make byte, etc., I receive the error message:

make: *** No rule to make target 'ocamlfind', needed by 'check'. Stop.

or

make: *** No rule to make target 'ocamlbuild', needed by 'byte'. Stop.

I'd appreciate help in understanding the cause of and solution to this error. Thanks.

Solution

  • This line:

    clean: $(OCB) -clean

    Means that clean has two dependencies, $(OCB) and -clean. So it tries to build ocamlbuild first.

    You want this, as in the linked makefile:

    clean:
        $(OCB) -clean

    This means that clean has no dependencies, and is "done" by running $(OCB) -clean.

    Note that you need an actual tab character before the $ character, not 8 spaces.