Makefiles are a simple way to organize code compilation. Using a makefile it is possible to compile several source files to produce an executable;

Transcription

1 Makefile Makefiles are a simple way to organize code compilation. Using a makefile it is possible to compile several source files to produce an executable; Source (.cc) and header (.h) files can be placed in different directories.

2 An example of code structure /Users/Pippo/ /Users/Pippo/Libs /Users/Pippo/Work (Library directory) (local working directory) froot.cc root_finders.cc proto.h

3 How it works Create a suitable makefile (see next) and then, from the terminal, simply type make This will assemble all source files and create the executable

4 The makefile EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $<

5 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< EXECUTABLE: this is the name of the final executable program

6 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< OBJECTS: a list of all the object files that must be linked together to produce the executable

7 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< CC: the name of the C++ compiler (or others) used to compile source codes

8 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< CFLAGS: list of flags to pass to the compilation command. Here -c means compile only and produce object file.o.

9 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< : location of the main source directory, where all of yours library routines are placed.this is not the local working directory.

10 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< VPATH: Special name used by GNU Make to specify a list of directories that make should search. Thus, if a file that is listed as a target or dependency does not exist in the current directory, make searches the directories listed in VPATH for a file with that name.

11 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< INCLUDE_DIRS: specifies the directories to be searched for header files. Note the usage of -I

12 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $< $(EXECUTABLE): this is the main target. It tells that the executable must be built from the object file list specified by $(OBJECTS). The second line is the actual command to be used to accomplish the target. The $@ says to put the output of the compilation in the file named on the left side of the :

13 EXECUTABLE = froot OBJECTS = froot.o root_finders.o CC = g++ CFLAGS = -c = /Users/mignone/Didattica/Algoritmi_Numerici/fisnum/lib VPATH =./:$() INCLUDE_DIRS = -I. -I$() LDFLAGS = -lm $(EXECUTABLE): $(OBJECTS) $(CC) $(OBJECTS) $(LDFLAGS) -o $@.cc.o: $(CC) $(CFLAGS) $(INCLUDE_DIRS) $<.cc.o: this is the suffix rule. It instruct how to create an object file (.o) from a source file (.cc). The $< is the first item in the dependencies list