The C compiler identification is unknown

Question

I want to compile a C program. When I run cmake

   build]$ cmake ../
    -- The C compiler identification is unknown
    -- Check for working C compiler: /usr/bin/cc
    -- Check for working C compiler: /usr/bin/cc -- broken
    CMake Error at /usr/share/cmake-3.0/Modules/CMakeTestCCompiler.cmake:61 (message):
      The C compiler "/usr/bin/cc" is not able to compile a simple test program.

It fails with the following output:

   Change Dir: /home/vahid/dev/Indexer/build/CMakeFiles/CMakeTmp

  Run Build Command:"/usr/bin/make" "cmTryCompileExec3431547622/fast"

  /usr/bin/make -f CMakeFiles/cmTryCompileExec3431547622.dir/build.make
  CMakeFiles/cmTryCompileExec3431547622.dir/build

  make[1]: Entering directory
  '/home/vahid/dev/Indexer/build/CMakeFiles/CMakeTmp'

  /usr/bin/cmake -E cmake_progress_report
  /home/vahid/dev/Indexer/build/CMakeFiles/CMakeTmp/CMakeFiles 1

  Building C object
  CMakeFiles/cmTryCompileExec3431547622.dir/testCCompiler.c.o

  /usr/bin/cc -o CMakeFiles/cmTryCompileExec3431547622.dir/testCCompiler.c.o
  -c /home/vahid/dev/Indexer/build/CMakeFiles/CMakeTmp/testCCompiler.c

  /usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.0/cc1: error while loading shared
  libraries: libisl.so.13: cannot open shared object file: No such file or
  directory

  CMakeFiles/cmTryCompileExec3431547622.dir/build.make:57: recipe for target
  'CMakeFiles/cmTryCompileExec3431547622.dir/testCCompiler.c.o' failed

  make[1]: *** [CMakeFiles/cmTryCompileExec3431547622.dir/testCCompiler.c.o]
  Error 1

  make[1]: Leaving directory
  '/home/vahid/dev/Indexer/build/CMakeFiles/CMakeTmp'

  Makefile:118: recipe for target 'cmTryCompileExec3431547622/fast' failed

  make: *** [cmTryCompileExec3431547622/fast] Error 2


  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:2 (project)


-- Configuring incomplete, errors occurred!
See also "/home/vahid/dev/Indexer/build/CMakeFiles/CMakeOutput.log".
See also "/home/vahid/dev/Indexer/build/CMakeFiles/CMakeError.log".

why did this error occur? How can I fix it?

Answer 1

why this error occured?

According to this error message:

/usr/bin/cc -o CMakeFiles/cmTryCompileExec3431547622.dir/testCCompiler.c.o -c /home/vahid/dev/Indexer/build/CMakeFiles/CMakeTmp/testCCompiler.c

/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.0/cc1: error while loading shared libraries: libisl.so.13: cannot open shared object file: No such file or directory

It looks like your compiler does not work.

how i can fix it?

Reinstall toolchain should be the simplest way to fix it.

How to do that depends on your operating system, if you are using Linux distribution like Debian, you can use something like apt-get install build-essential to install it; if you are using Fedora or CentOS, you could use yum group install c-development.