CODEWITHSUNDEEP
c++gcccmakeversion
Caduchon
Caduchon

Reputation: 5191

CMake find wrong gcc version

My problem is simple : if I check the gcc version, I obtain 4.5.1, but CMake find gcc 4.5.0 :

> /usr/bin/gcc --version
gcc (SUSE Linux) 4.5.1 20101208 [gcc-4_5-branch revision 167585]
Copyright (C) 2010 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> mkdir BUILD & cd BUILD
> cmake ..
-- The C compiler identification is GNU 4.5.0
-- The CXX compiler identification is GNU 4.5.0
-- Check for working C compiler: /usr/bin/gcc
-- Check for working C compiler: /usr/bin/gcc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- The Fortran compiler identification is GNU
-- Check for working Fortran compiler: /usr/bin/gfortran
-- Check for working Fortran compiler: /usr/bin/gfortran  -- works
-- Detecting Fortran compiler ABI info
-- Detecting Fortran compiler ABI info - done
-- Checking whether /usr/bin/gfortran supports Fortran 90
-- Checking whether /usr/bin/gfortran supports Fortran 90 -- yes

Who is wrong ? CMake or Gcc ?

I use cmake 2.8.9, but I also have the bug with cmake 3.1.0.

I don't have the bug with gcc 4.7.2, 4.4.7 and 4.1.2.

Upvotes: 5

Views: 13315

Answers (3)

Mike T
Mike T

Reputation: 43612

The solution I found was similar to @usr1234567 that essentially CMake uses cc and c++ wherever they are off the $PATH, which is not always the same as gcc or g++.

Specifying these compilers fixes the version shown by CMake:

cmake -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ ..

Upvotes: 12

Caduchon
Caduchon

Reputation: 5191

Answering my own question.

Actually, gcc 4.5.1 seems have a bug because the following simple code (correct according to the official doc : https://gcc.gnu.org/onlinedocs/cpp/Common-Predefined-Macros.html) prints 4.5.0 when compiled with gcc 4.5.1 on my workstation.

#include <iostream>
int main(int argc, char** argv)
{
  std::cout << __GNUC__ << "." << __GNUC_MINOR__ << "." << __GNUC_PATCHLEVEL__ << std::endl;
  return 0;
}

Upvotes: 1

usr1234567
usr1234567

Reputation: 23294

CMake uses /usr/bin/c++ probably this is still pointing to gcc 4.5.0. If you want to set the compiler, add -DCMAKE_CXX_COMPILER to the compiler you like.

Upvotes: 1

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