cmake complains g++-7 is not able to compile a simple test program.

Just install gcc-7 package from buster repo and cmake complains with this error message c++: fatal error: '-c' is not a valid option to the preprocessor as shown below. Has anyone seen this issue?

 CMake Error at /usr/share/cmake-3.10/Modules/CMakeTestCXXCompiler.cmake:45 (message):
   The C++ compiler

     "/usr/bin/c++"

   is not able to compile a simple test program.

   It fails with the following output:

     Change Dir: /home/local/PEOPLE/debian/works/C++/BMP/bmp-6/build/CMakeFiles/CMakeTmp

     Run Build Command:"/usr/bin/make" "cmTC_3f125/fast"
     /usr/bin/make -f CMakeFiles/cmTC_3f125.dir/build.make CMakeFiles/cmTC_3f125.dir/build
     make[1]: Entering directory '/home/local/PEOPLE/debian/works/C++/BMP/bmp-6/build/CMakeFiles/CMakeTmp'
     Building CXX object CMakeFiles/cmTC_3f125.dir/testCXXCompiler.cxx.o
     /usr/bin/c++     -o CMakeFiles/cmTC_3f125.dir/testCXXCompiler.cxx.o -c
 /home/local/PEOPLE/debian/works/C++/BMP/bmp-6/build/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
     c++: fatal error: '-c' is not a valid option to the preprocessor
     compilation terminated.
     CMakeFiles/cmTC_3f125.dir/build.make:65: recipe for target 'CMakeFiles/cmTC_3f125.dir/testCXXCompiler.cxx.o' failed
     make[1]: *** [CMakeFiles/cmTC_3f125.dir/testCXXCompiler.cxx.o] Error 1
     make[1]: Leaving directory '/home/local/PEOPLE/debian/works/C++/BMP/bmp-6/build/CMakeFiles/CMakeTmp'
     Makefile:126: recipe for target 'cmTC_3f125/fast' failed
     make: *** [cmTC_3f125/fast] Error 2

If you run c++ --help is -c listed as an option?

Hi habibie,

Please keep all gcc-7 in this same topic. No need to create new thread for different gcc-7 problem.

-bodhi
===========================
Forum Wiki
bodhi's corner (buy bodhi a beer)

renojim Wrote:
-------------------------------------------------------
> If you run c++ --help is -c listed as an option?
>
Yes and indeed -c listed as an option. So, it ought to be a cmake problem?

[root@debian:/root 4%] # c++ --help
Usage: c++ [options] file...
Options:
  -pass-exit-codes         Exit with highest error code from a phase.
  --help                   Display this information.
  --target-help            Display target specific command line options.
  --help={common|optimizers|params|target|warnings|[^]{joined|separate|undocumented}}[,...].
                           Display specific types of command line options.
  (Use '-v --help' to display command line options of sub-processes).
  --version                Display compiler version information.
  -dumpspecs               Display all of the built in spec strings.
  -dumpversion             Display the version of the compiler.
  -dumpmachine             Display the compiler's target processor.
  -print-search-dirs       Display the directories in the compiler's search path.
  -print-libgcc-file-name  Display the name of the compiler's companion library.
  -print-file-name=<lib>   Display the full path to library <lib>.
  -print-prog-name=<prog>  Display the full path to compiler component <prog>.
  -print-multiarch         Display the target's normalized GNU triplet, used as
                           a component in the library path.
  -print-multi-directory   Display the root directory for versions of libgcc.
  -print-multi-lib         Display the mapping between command line options and
                           multiple library search directories.
  -print-multi-os-directory Display the relative path to OS libraries.
  -print-sysroot           Display the target libraries directory.
  -print-sysroot-headers-suffix Display the sysroot suffix used to find headers.
  -Wa,<options>            Pass comma-separated <options> on to the assembler.
  -Wp,<options>            Pass comma-separated <options> on to the preprocessor.
  -Wl,<options>            Pass comma-separated <options> on to the linker.
  -Xassembler <arg>        Pass <arg> on to the assembler.
  -Xpreprocessor <arg>     Pass <arg> on to the preprocessor.
  -Xlinker <arg>           Pass <arg> on to the linker.
  -save-temps              Do not delete intermediate files.
  -save-temps=<arg>        Do not delete intermediate files.
  -no-canonical-prefixes   Do not canonicalize paths when building relative
                           prefixes to other gcc components.
  -pipe                    Use pipes rather than intermediate files.
  -time                    Time the execution of each subprocess.
  -specs=<file>            Override built-in specs with the contents of <file>.
  -std=<standard>          Assume that the input sources are for <standard>.
  --sysroot=<directory>    Use <directory> as the root directory for headers
                           and libraries.
  -B <directory>           Add <directory> to the compiler's search paths.
  -v                       Display the programs invoked by the compiler.
  -###                     Like -v but options quoted and commands not executed.
  -E                       Preprocess only; do not compile, assemble or link.
  -S                       Compile only; do not assemble or link.
  -c                       Compile and assemble, but do not link.
  -o <file>                Place the output into <file>.
  -pie                     Create a position independent executable.
  -shared                  Create a shared library.
  -x <language>            Specify the language of the following input files.
                           Permissible languages include: c c++ assembler none
                           'none' means revert to the default behavior of
                           guessing the language based on the file's extension.

Options starting with -g, -f, -m, -O, -W, or --param are automatically
 passed on to the various sub-processes invoked by c++.  In order to pass
 other options on to these processes the -W<letter> options must be used.

For bug reporting instructions, please see:
<file:///usr/share/doc/gcc-7/README.Bugs>.
[root@debian:/root 5%] #

Did you also install g++-7 when you installed gcc-7? If not, try to install it the same way you installed gcc-7.

-JT

renojim Wrote:
-------------------------------------------------------
> Did you also install g++-7 when you installed gcc-7? If not, try to install it the same way you installed gcc-7.
>
> -JT
>
I did forget to install g++-7 package. However, after installing the g++-7 package, the problem remains the same. When I used the -o switch, it seemed to compile a simple hello.c++ file. However, the compiled hello isn't executable, but rather an ASCII text file (see below). This probably means the gcc-7 package I installed from buster repo is useless.

[debian@debian:/home/local/PEOPLE/debian/works/C++ 62%] ~ g++ -c hello.c++
g++: fatal error: ‘-c’ is not a valid option to the preprocessor
compilation terminated.
[debian@debian:/home/local/PEOPLE/debian/works/C++ 63%] ~ g++ -o hello hello.c++
[debian@debian:/home/local/PEOPLE/debian/works/C++ 64%] ~ ls -la
total 664
drwxr-xr-x  3 debian users   4096 Mar 18 00:55 .
drwxr-xr-x  4 debian users   4096 Mar 18 00:37 ..
drwxr-xr-x 17 debian users   4096 Dec  3 13:50 BMP
-rw-r--r--  1 debian users 661956 Mar 18 00:55 hello
-rw-r--r--  1 debian users    102 Mar 18 00:53 hello.c++
[debian@debian:/home/local/PEOPLE/debian/works/C++ 65%] ~ file hello
hello: C++ source, ASCII text
[debian@debian:/home/local/PEOPLE/debian/works/C++ 66%] ~

Try running g++ with the -v option. Maybe it will tell us something.