This will cause a fatal error if ENV is undefined and something needs it (in GNUMake, anyway). .PHONY: deploy check-env deploy: check-env … other-thing-that-needs-env: check-env … check-env: ifndef ENV $(error ENV is undefined) endif (Note that ifndef and endif are not indented – they control what make “sees”, taking effect before the Makefile is run. … Read more
The fundamental issue with Make and Java is that Make works on the premise that you have specify a dependency, and then a rule to resolve that dependency. With basic C, that typically “to convert a main.c file to a main.o file, run “cc main.c”. You can do that in java, but you quickly learn … Read more
You can do this with make – with gnu make it is the -j flag (this will also help on a uniprocessor machine). For example if you want 4 parallel jobs from make: make -j 4 You can also run gcc in a pipe with gcc -pipe This will pipeline the compile stages, which will … Read more
Try the -i flag (or –ignore-errors). The documentation seems to suggest a more robust way to achieve this, by the way: To ignore errors in a command line, write a – at the beginning of the line’s text (after the initial tab). The – is discarded before the command is passed to the shell for … Read more
That message is usually an indication that some of your files have modification times later than the current system time. Since make decides which files to compile when performing an incremental build by checking if a source files has been modified more recently than its object file, this situation can cause unnecessary files to be … Read more
It depends on the package. If the Makefile is generated by GNU autotools (./configure) you can usually set the target location like so: ./configure –prefix=/somewhere/else/than/usr/local If the Makefile is not generated by autotools, but distributed along with the software, simply open it up in an editor and change it. The install target directory is probably … Read more
Make variables are not exported into the environment of processes make invokes… by default. However you can use make’s export to force them to do so. Change: test: NODE_ENV = test to this: test: export NODE_ENV = test (assuming you have a sufficiently modern version of GNU make >= 3.77 ).
TL;DR: Use the error function: ifndef MY_FLAG $(error MY_FLAG is not set) endif Note that the lines must not be indented. More precisely, no tabs must precede these lines. Generic solution In case you’re going to test many variables, it’s worth defining an auxiliary function for that: # Check that given variables are set and … Read more
You can use Target-specific Variable Values. Example: CXXFLAGS = -g3 -gdwarf2 CCFLAGS = -g3 -gdwarf2 all: executable debug: CXXFLAGS += -DDEBUG -g debug: CCFLAGS += -DDEBUG -g debug: executable executable: CommandParser.tab.o CommandParser.yy.o Command.o $(CXX) -o output CommandParser.yy.o CommandParser.tab.o Command.o -lfl CommandParser.yy.o: CommandParser.l flex -o CommandParser.yy.c CommandParser.l $(CC) -c CommandParser.yy.c Remember to use $(CXX) or $(CC) … Read more
It means “don’t echo this command on the output.” So this rule is saying “execute the shell command : and don’t echo the output. Of course the shell command : is a no-op, so this is saying “do nothing, and don’t tell.” Why? The trick here is that you’ve got an obscure combination of two … Read more