A function part of CGLSLProgram class (any class that to manage GLSL program/shaders in GLSL) to print the active Uniforms and Attributes variables in our shaders.

CGLSLProgram.cpp

// We assume that the location of GLSL program is stored in the variable <code>m_uIdProgram</code> as an unsigned int
// #include <iomanip> is necessary to use of setw (text formatting)
void CGLSLProgram::showDebugging()
{
  GLint iMaxLength, iNumAttrib, iNumUniform;
  glGetProgramiv(m_uIdProgram, GL_ACTIVE_ATTRIBUTES, &iNumAttrib);
  glGetProgramiv(m_uIdProgram, GL_ACTIVE_ATTRIBUTE_MAX_LENGTH, &iMaxLength);
  GLchar* name = new GLchar[iMaxLength];
  GLint written, size, location;
  GLenum type;
  std:cout << "Index | Attribute Name" << std::endl;
  std::cout << std::string(23, '-') << std::endl;
  for(int i = 0; i < iNumAttrib; i++)
  {
    glGetActiveAttrib(m_uIdProgram, i, iMaxLength, &written, &size, &type, name);
    location = glGetAttribLocation(m_uIdProgram, name);
    std::cout << setw(5) << location << " | " << name << "," << std::endl;
  }
  delete name;
  glGetProgramiv(m_uIdProgram, GL_ACTIVE_UNIFORMS, &iNumUniform);
  glGetProgramiv(m_uIdProgram, GL_ACTIVE_UNIFORM_MAX_LENGTH, &iMaxLength);
  name = new GLchar[iMaxLength];
  std::cout << "Index | Uniform Name" << std::endl;
  std::cout << std::string(21, '-') << std::endl;
  for (int i = 0; i < iNumUniform; i++)
  {
    glGetActiveUniform(m_uIdProgram, i, iMaxLength, &written, &size, &type, name);
    location = glGetUniformLocation(m_uIdProgram, name);
    std::cout << setw(5) << location << " | " << name << "," << std::endl;
  }
  delete name;
}