Make Basics

Naming

Rule

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "do something"

Target

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "do something"

First prerequisite

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "do something"

All prerequisites

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "do something"

Recipe
Each line of the recipe is executed in a new shell, except .ONESHELL is defined (see here).
```
foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "do something"
```

Automatic Variables

Direct variables:

$@: The target of the rule

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "$@"

$<: The first prerequisite

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "$<"

$?: All prerequisites that are newer than the target

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h
	echo "$?"

$^: All prerequisites (no dupplicates)

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h include1.h
	echo "$^"

$+: All prerequisites (with dupplicates)

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h include1.h
	echo "$+"

$|: All order-only prerequisites

foo/myfile.o: bar/myfile.c myfile.h include1.h include2.h | linux-folder
	echo "$|"

$*: see manual

a.%.b: bar/myfile.c myfile.h include1.h include2.h
	echo "dir/a.foo.b  = $*"   # dir/a.foo.b  = dir/foo

Modified variables:

$(@D): The directory part of the file name of the target, with the trailing slash removed
```
foo/bar/myfile.o: myfile.c myfile.h include1.h include2.h
	echo "$(@D)"
```

$(@F): The file-within-directory part of the file name of the target

foo/bar/myfile.o: myfile.c myfile.h include1.h include2.h
	echo "$(@F)"

$(<D): The directory part of the first prerequisite

myfile.o: foo/myfile.c bar/myfile.h doo/include1.h dar/include2.h
	echo "$(<D)"

$(<F): The file-within-directory part of the first prerequisite

myfile.o: foo/myfile.c bar/myfile.h doo/include1.h dar/include2.h
	echo "$(<F)"

$(?D): Lists of the directory parts of all prerequisites that are newer than the target
```
myfile.o: foo/myfile.c bar/myfile.h doo/include1.h dar/include2.h
	echo "$(?D)"
```
$(?F): Lists of the file-within-directory parts of all prerequisites that are newer than the target
```
myfile.o: foo/myfile.c bar/myfile.h doo/include1.h dar/include2.h
	echo "$(?F)"
```

$(^D): Lists of the directory parts of all prerequisites

myfile.o: foo/myfile.c bar/myfile.h doo/include1.h dar/include2.h
	echo "$(^D)"

$(^F): Lists of the file-within-directory parts of all prerequisites

myfile.o: foo/myfile.c bar/myfile.h doo/include1.h dar/include2.h
	echo "$(^F)"

Source: gnu.org

Force Execution

When having targets which e.g. run the application, you want to have it performed on every call, independent if the dependencies have changed or not. For this you can introduce a FORCE target:

run: $(TARGET) FORCE
        ./$< | ts %.s

FORCE:

Recipes

see https://www.gnu.org/software/make/manual/make.html#Recipes

Implicit Rules

https://www.gnu.org/software/make/manual/html_node/Implicit-Rules.html#Implicit-Rules