Takes a built-in scalar or vector data type argument and returns an integer value representing the number of elements in the scalar or vector.
int vec_step(gentypen a); int vec_step(char3 a); int vec_step(uchar3 a); int vec_step(short3 a); int vec_step(ushort3 a); int vec_step(half3 a); int vec_step(int3 a); int vec_step(uint3 a); int vec_step(long3 a); int vec_step(ulong3 a); int vec_step(float3 a); int vec_step(double3 a); int vec_step(type);
The vec_step built-in function takes a built-in scalar or vector data type argument and returns an integer value representing the number of elements in the scalar or vector.
For all scalar types, vec_step returns 1.
The vec_step built-in functions that take a 3-component vector return 4.
vec_step may also take a pure type as an argument, e.g. vec_step(float2)
We use the generic type name gentypen (or gentypem) to indicate the built-in data types char{2|4|8|16}, uchar{2|4|8|16}, short{2|4|8|16}, ushort{2|4|8|16}, int{2|4|8|16}, uint{2|4|8|16}, long{2|4|8|16}, ulong{2|4|8|16}, or float{2|4|8|16} as the type for the arguments unless otherwise stated. We use the generic name ugentypen to indicate the built-in unsigned integer data types. If the double is supported, then gentypen (or gentypem) also indicate the built-in data types double{2|4|8|16}.
The generic type name gentypen (or gentypem) may indicate the data type half{2|4|8|16} if the cl_khr_fp16(3clc) extension is supported.
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miscVectorFunctions(3clc)
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OpenCL Specification
page 282, section 6.12.12 Miscellaneous Vector Functions