OpenGL Mac OSX vertex shader not linking to fragment shader

Question

I'm having problems to compile and execute a simple OpenGL application in Mac OSX 10.9. It works just fine in windows. But in Mac I keep getting some errors while linking the vertex shader to the fragment shader in the shaderProgram.

Here is my console Output.

4.1 INTEL-8.26.34

ERROR! could not link the shader program
WARNING: Output of vertex shader 'outColor' not read by fragment shader
ERROR: Input of fragment shader 'inColor' not written by vertex shader
Program ended with exit code: 0

Here is the Method that I'm using to link both together.

GLuint createShaderProgram(GLuint vertexShader, GLuint fragmentShader)
{
    // Create and link the shader program
    GLuint shaderProgram = glCreateProgram(); // create handle
    if (!shaderProgram) {
    ERROR("could not create the shader program", false);
    return NULL_HANDLE;
    }
    glAttachShader(shaderProgram, vertexShader);    // attach vertex shader
    glAttachShader(shaderProgram, fragmentShader);  // attach fragment shader
    glLinkProgram(shaderProgram);



    // check to see if the linking was successful
    int linked;
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &linked); // get link status
    if (!linked) {
        ERROR("could not link the shader program", false);
        int maxLength;
        int length;
        glGetProgramiv(shaderProgram, GL_INFO_LOG_LENGTH, &maxLength);
        char* log = new char[maxLength];
        glGetProgramInfoLog(shaderProgram, maxLength,&length,log);
        printf(log);

        return NULL_HANDLE;
    }

    return shaderProgram;
}

Here is my vertexshader.

#version 410 core
layout (location = 0) in vec3 inPosition;
layout (location = 3) in vec3 inColor;
layout (location = 3) smooth out vec4 outColor;
void main()
{   
    gl_Position = vec4(inPosition, 1.0);
    outColor = vec4(inColor, 1.0);
}

Here is the fragShader

#version 410 core
layout (location = 3) smooth in vec4 inColor;
layout (location = 0) out vec4 outColor;
void main()
{
    outColor = inColor;
}

Thanks!!

Answer 1

the names need to match:

have the name of the output of the vertex shader match the name of the input of the fragment shader:

#version 410 core
layout (location = 0) in vec3 inPosition;
layout (location = 3) in vec3 inColor;
smooth out vec4 vertOutColor;
void main()
{   
    gl_Position = vec4(inPosition, 1.0);
    vertOutColor = vec4(inColor, 1.0);
}

fragment shader:

#version 410 core
smooth in vec4 vertOutColor;
layout (location = 0) out vec4 outColor;
void main()
{
    outColor = vertOutColor;
}