CODEWITHSUNDEEP
c++makefilelinker
Pierre P.
Pierre P.

Reputation: 1065

Makefile with headers and linker

I'm currently working on creating a Makefilefor my simple c++ application.

At the moment, I'd like to compile a unique file, main.cpp with the following headers and linker 

g++ main.cpp -L/usr/local/Cellar/boost/1.65.1/lib -I/usr/local/Cellar/boost/1.65.1/include -lboost_system

When I prompt this command in the terminal, everything works well. However, when put into a Makefile 

SRC_FILES=main.cpp
LDLIBS=-L/usr/local/Cellar/boost/1.65.1/lib -I/usr/local/Cellar/boost/1.65.1/include
LD=-lboost_system

main.cpp:
    g++ main.cpp ${LDLIBS} ${LD}

and try to run make -f Makefile main, it doesn't compile. 

Undefined symbols for architecture x86_64:
  "boost::system::system_category()", referenced from:
      boost::asio::error::get_system_category() in main-100974.o
      ___cxx_global_var_init.2 in main-100974.o
  "boost::system::generic_category()", referenced from:
      ___cxx_global_var_init in main-100974.o
      ___cxx_global_var_init.1 in main-100974.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [main] Error 1

Looks like the argument are not correctly passed.

N.B : When I try to run make -f Makefile main.cpp, the compiler tells me that main.cpp is already up-to-date

I assume I'm doing something wrong within the Makefile, but don't know what.

Thanks for your help,

Upvotes: 0

Views: 34

Answers (1)

Slava
Slava

Reputation: 44238

In Makefile on the left of : you define target, not source:

main.cpp:

tells make how to create main.cpp if it does not exist or older than dependencies (which are on the right of : in your case is nothing). You need to give your program a name and put that as a target:

programname: main.cpp
      g++ main.cpp ${LDLIBS} ${LD} -o programname

Upvotes: 1

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