I have the following makefile

SRCS = a.cpp
OBJS = $(SRCS:.cpp=.o)

all:    $(MAIN)
    @echo  Compiled successfully

$(MAIN): $(OBJS)
    $(CXX) $(LFLAGS) $(CFLAGS) $(INCLUDES) -o $(MAIN) $(OBJS) $(LFLAGS) $(LIBS)


.cpp.o:
    $(CXX) $(LFLAGS) $(CFLAGS) $(INCLUDES) -c $<  -o $@

When I run make all initially no .o files exist hence the .cpp.o: rule is executed (a.o: a.cpp), and then I see the $(MAIN): rule being executed – however – it seems like the $(MAIN): rule is executed before the a.o object file is created, and make fails saying that the ‘a.o’ file could not be found..

This doesn’t happen all the time, which suggests some race condition, which could happen if the $(MAIN): rule does not ‘wait’ until the .cpp.o: has finished..