Chapter 2, Snippet 12 - OpenGLBook.com

chapter.2.12.c

void DestroyShaders(void)
{
  GLenum ErrorCheckValue = glGetError();

  glUseProgram(0);

  glDetachShader(ProgramId, VertexShaderId);
  glDetachShader(ProgramId, FragmentShaderId);

  glDeleteShader(FragmentShaderId);
  glDeleteShader(VertexShaderId);

  glDeleteProgram(ProgramId);

  ErrorCheckValue = glGetError();
  if (ErrorCheckValue != GL_NO_ERROR)
  {
    fprintf(
      stderr,
      "ERROR: Could not destroy the shaders: %s \n",
      gluErrorString(ErrorCheckValue)
    );

    exit(-1);
  }
}