0

I suppose this question is asked in some other threads, I was getting the error while calling make: to_string is not declared in this scope. I found out I have to add c++11 in makefile. But I tried some options mentioned in several threads. Could you provide some solution here? Thanks

naman arora
  • 51
  • 7
  • 2
    can you post a minimal complete example please so that we can start to think about what might be wrong? – Richard Hodges Aug 12 '15 at 08:14
  • This is my makefile http://1drv.ms/1JTD6T6, I could not add all the contents due to space limit – naman arora Aug 12 '15 at 08:14
  • I presume you're using g++. This compiler is strong on standard-conformance for the core language, but weak on the standard library (takes long to catch up). Thus there is a distinct possibility that `to_string` is actually missing, depending on the version. Complementing this, Microsoft's compiler is weak on standard-conformance for the core language, but strong on the standard library. Perhaps due to efforts of STL. (That's a person, not the Standard Template Library: at Microsoft, STL maintains the STL). – Cheers and hth. - Alf Aug 12 '15 at 08:20
  • @namanarora: please do narrow your code down to a **minimal but complete example**. thank you. – Cheers and hth. - Alf Aug 12 '15 at 08:22
  • @Cheers and hth. - Alf Is this ok? I am not sure about minimal but complete example, these are the contents of the make file, other things are normal, probably here is some thing missing: CC=g++ LD=g++ CFLAGS=-c -g -O3 -finline-functions -fstack-protector – naman arora Aug 12 '15 at 08:23
  • And I also ran on Mac, it was working there – naman arora Aug 12 '15 at 08:27

1 Answers1

1

Adding -std=c++11 to CFLAGS will cause g++ to compile with the C++11 standard. Like this

CFLAGS=-std=c++11 -c -g -O3 -finline-functions -fstack-protector

However, as highlighted in comments the appropriate syntax for compiling C++ programs with a makefile is to use a rule like this

$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c

where your C++ files use the suffix .cc [1]. Then you would add -std=c++11 to CXXFLAGS. The difference between CPPFLAGS and CXXFLAGS is [2]

CPPFLAGS is supposed to be for flags for the C PreProcessor; CXXFLAGS is for flags for the C++ compiler.

This would require some rewrites within your makefile, namely

CXX=g++
LD=g++
CXXFLAGS=-c -g -O3 -fstack-protector -I./Eigen

and rules from

$(CC) $(INCLUDE) $(CFLAGS) -c

to 

$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c

as above.

The $(INCLUDE) can also be removed from your linking command ($(LD)) as it is only needed during compile time. Your linking command can also be simplified to

ParEGOIteration13: ParEGOIteration13.o Utilities.o WeightVector.o SearchSpace.o DACE.o GeneticAlgorithm.o Matrix.o
    $(CXX) $? -o $@

by using the automatic variables [3]

  • $? expands to all of the prerequisites
  • $@ expands to the name of the target

I'll let you work out how to use the automatic variables in your compilation rules.

Note: I've removed -finline-functions as -O3 (and -O2) turn it on by default with gcc.

IKavanagh
  • 6,089
  • 11
  • 42
  • 47
  • Actually that should be `CXXFLAGS` not `CFLAGS` ;) – Drax Aug 12 '15 at 08:53
  • In the `makefile` posted in the comments that would require much more significant changes. – IKavanagh Aug 12 '15 at 08:58
  • "much more significant change", you mean also changing `CC` to `CXX` ? The guy is learning things, doesn't hurt to give him full infos/advice while you're at it :) – Drax Aug 12 '15 at 09:00
  • @Drax I've updated the answer based on your comments. I think I've covered most of the basics to help the guy out now. – IKavanagh Aug 12 '15 at 09:37
  • Holy cow, didn't expect that much, nice answer :) – Drax Aug 12 '15 at 09:45