--- layout: stdlib-reference --- # countbits ## Description Population count. Counts the number of set bits in the binary representation of a value. ## Signature

uint countbits<T>(T value)
    where T : __BuiltinIntegerType;

vector<uint, N> countbits<T, int N>(vector<T, N> value)
    where T : __BuiltinIntegerType;

## Generic Parameters #### T: [\_\_BuiltinIntegerType](../interfaces/0_builtinintegertype-029g/index.html) #### N : int ## Parameters #### value : [T](countbits.html#typeparam-T) The value to count bits in. #### value : [vector](../types/vector/index.html)\<[T](../types/vector/index.html#typeparam-T), [N](../types/vector/index.html#decl-N)\> The value to count bits in. ## Return value The number of bits in the binary representation of value that are set to one. ## Remarks For SPIR-V, this function maps to OpBitCount. ## Availability and Requirements Defined for the following targets: #### hlsl Available in all stages. #### glsl Available in all stages. #### cpp Available in all stages. #### cuda Available in all stages. #### metal Available in all stages. #### wgsl Available in all stages. #### spirv Available in all stages.