Light_ambient; | Together C & C++ | Page 1

i do not the get ambient lighting to work.
are there something that is missing.

struct S_L //Spotlight
{
    DirectX::XMFLOAT3 pos;     
    DirectX::XMFLOAT4 Light_ambient;  
    float range;                
    DirectX::XMFLOAT3 dir;      
    float cone;                
    DirectX::XMFLOAT3 att;      
    float k;                
    DirectX::XMFLOAT4 diffuse; 

};
bool spotlight(ID3D11Device* device, ID3D11Buffer*& constentBuffer_spotlight) {

    S_L light{};

    light.Light_ambient = DirectX::XMFLOAT4(1.0f, 1.0f, 1.0f, 1.0f);
    light.k = 0.05f;

    D3D11_BUFFER_DESC BufferDesc_matrix;
    BufferDesc_matrix.ByteWidth = sizeof(S_L);
    BufferDesc_matrix.Usage = D3D11_USAGE_IMMUTABLE;
    BufferDesc_matrix.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
    BufferDesc_matrix.CPUAccessFlags = 0;
    BufferDesc_matrix.MiscFlags = 0,
    BufferDesc_matrix.StructureByteStride = 0;

    D3D11_SUBRESOURCE_DATA data_1;
    data_1.pSysMem = &light;
    data_1.SysMemPitch = 0;
    data_1.SysMemSlicePitch = 0;

    HRESULT hr = device->CreateBuffer(&BufferDesc_matrix, &data_1, &constentBuffer_spotlight);
    return !FAILED(hr);

}

Texture2D texture1;
SamplerState Sampler;

struct PixelShaderInput
{
    float4 position : SV_POSITION;
    float3 normal : NORMAL;
    float2 UV : UV;
    float4 World_pos : world_pos;
       
};

cbuffer S_L : register(b0) //Spotlight
{
    float3 pos;     
    float4 Light_ambient; 
    float range;    
    float3 dir;     
    float cone;     
    float3 att;    
    float k;        
    float4 diffuse; 
};

float4 main(PixelShaderInput input) : SV_TARGET
{
    
    float4 c = Light_ambient * k;
    
    float4 sampling = texture1.Sample(Sampler, input.UV) * c;
    return sampling;    
}

#Light_ambient;