CODEWITHSUNDEEP
c++linuxcompilation
Sohrab
Sohrab

Reputation: 135

How do I compile a project with multiple source files?

I have a main code (.cpp) and some other files (.cpp and their corresponding .h file) which contain the function that are used in my main program. I'd like to know how to compile my files and run the main code.

Upvotes: 5

Views: 17373

Answers (3)

ruakh
ruakh

Reputation: 183554

This depends on your compiler. For example, with GCC you might write:

g++ foo.cpp bar.cpp baz.cpp -o foo # compile program
./foo                              # run program

Upvotes: 8

sarnold
sarnold

Reputation: 104090

Basile's right on, you need build machinery to have software you can easily work on. You really want to be able to just run make or something similar and get your project re-built quickly in a repeatable fashion. You also want to make sure that your entire project is kept up to date, rebuilding everything that depends upon something that has changed. While you could just keep around a shell script containing g++ lines as in ruakh's answer, this will needlessly recompile more than you need. (Which isn't a big deal with small projects but becomes important when projects grow larger than trivial.)

I've only taken fifteen minutes to skim the OMake documentation, but it looks very promising. make is standard on systems and provides a huge array of pre-defined build rules, including rules for C++, so it isn't very difficult to write new Makefiles for projects.

It'll look something like this:

# the compiler and its flags
CXX = g++
CXXFLAGS = -Wall

PROGRAM = foo

OBJECTS = foo_a.o foo_b.o foo_c.o foo_d.o

.PHONY: all

.DEFAULT: all

all: $(PROGRAM)

$(PROGRAM): $(OBJECTS)

The objects foo_a.o will be built from a corresponding source file named foo_a.c, foo_a.cc, foo_a.C, foo_a.cpp, foo_a.p, foo_a.f, foo_a.F, etc., for C, C++, Fortran, Pascal, Lex, Yacc, and so on.

The O'Reilly make book is sadly quite dated at this point; the .SUFFIX rules have been supplanted by pattern rules, but there is no coverage of pattern rules in the O'Reilly book. That said, it is still a good starting point if the full GNU Make documentation isn't a good fit for you.

Upvotes: 6

Basile Starynkevitch
Basile Starynkevitch

Reputation: 1

But the real answer is to use some build machinery, like e.g. have a Makefile and use GNU Make.

There are some better builder than GNU Make, like Omake

Builders are very useful, because in the example by ruakh you may don't want to recompile foo.cpp when only bar.cpp changed so you need to take dependencies into account.

(and there are Makefile generators, like automake, cmake ...)

Upvotes: 1

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