AMD compiller throwing "function declared implicitly"

I was trying to make my kernel compile, and the compiler threw this error:
C:\Users\SAMYRA~1\AppData\Local\Temp\", line 27: error: function
“cltocppfloat” declared implicitly
out[num] = cltocppfloat(out[num]);

Here is my kernel:
#include “clVecMath.h”

struct cppfloat4{
float x;
float y;
float z;
float w;

struct cppfloat4 cltocppfloat4(float4 a){
struct cppfloat4 b;
b.x = a.x;
b.y = a.y;
b.z = a.z;
b.w = a.w;

float4 cppfloat4tocl(struct cppfloat4 a){
return ((float4)(a.x, a.y, a.z, a.w));

__kernel void helloworld(__global float4* in, __global int* multiplier, __global float4* out)
int num = get_global_id(0);
out[num] = rotateAxis(in[num], (float4)(1.0f, 0.0f, 0.0f, 0.0f), multiplier[num]);
out[num] = cltocppfloat(out[num]);

I do not see any reason while this error is thrown.

The function you’ve defined is called cltocppfloat4, but the function you are trying to call is called cltocppfloat.