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NAME
Scalar_Data_Types - Built-in scalar data types.
DESCRIPTION
These are the data types available in the OpenCL C programming language used to create kernels that are
executed on OpenCL device(s). The OpenCL C programming language (also referred to as OpenCL C) is based
on the ISO/IEC 9899:1999 C language specification (a.k.a. C99 specification) with specific extensions and
restrictions. Please refer to the ISO/IEC 9899:1999 specification for a detailed description of the
language grammar. This section describes modifications and restrictions to ISO/IEC 9899:1999 supported in
OpenCL C.
Most built-in scalar data types are also declared as appropriate types in the OpenCL API (and header
files) that can be used by an application. The following table describes the built-in scalar data type in
the OpenCL C programming language and the corresponding data type available to the application:
┌───────────────────────────┬──────────────────────────────┬──────────────────────────┐
│Type in OpenCL C Language │ Description │ API type for application │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│bool │ A conditional data type │ n/a │
│ │ which is either true or │ │
│ │ false. The value true │ │
│ │ expands to the integer │ │
│ │ constant 1 and the value │ │
│ │ false expands to the integer │ │
│ │ constant 0. When any scalar │ │
│ │ value is converted to bool, │ │
│ │ the result is 0 if the value │ │
│ │ compares equal to 0; │ │
│ │ otherwise, the result is 1. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│char │ A signed two's complement │ cl_char │
│ │ 8-bit integer. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│ unsigned char, │ An unsigned 8-bit integer. │ cl_uchar │
│ uchar │ │ │
│ │ │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│short │ A signed two's complement │ cl_short │
│ │ 16-bit integer. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│ unsigned short, │ An unsigned 16-bit integer. │ cl_ushort │
│ ushort │ │ │
│ │ │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│int │ A signed two's complement │ cl_int │
│ │ 32-bit integer. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│ unsigned int, │ An unsigned 32-bit integer. │ cl_uint │
│ uint │ │ │
│ │ │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│long │ A signed two's complement │ cl_long │
│ │ 64-bit integer. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│ unsigned long, │ An unsigned 64-bit integer. │ cl_ulong │
│ ulong │ │ │
│ │ │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│float │ A 32-bit floating point. The │ cl_float │
│ │ float data type must conform │ │
│ │ to the IEEE 754 single │ │
│ │ precision storage format. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│double │ A 64-bit floating point. The │ cl_double │
│ │ double data type must │ │
│ │ conform to the IEEE 754 │ │
│ │ double precision storage │ │
│ │ format. The double scalar │ │
│ │ type is an optional type │ │
│ │ that is supported if │ │
│ │ CL_DEVICE_DOUBLE_FP_CONFIG │ │
│ │ for a device is not zero. │ │
│ │ See the table for param_name │ │
│ │ for clGetDeviceInfo(3clc) │ │
│ │ for details. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│half │ A 16-bit float. The half │ cl_half │
│ │ data type must conform to │ │
│ │ the IEEE 754-2008 half │ │
│ │ precision storage format. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│size_t │ The unsigned integer type of │ n/a │
│ │ the result of the sizeof │ │
│ │ operator. This is a 32-bit │ │
│ │ unsigned integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS │ │
│ │ defined in │ │
│ │ clGetDeviceInfo(3clc) is │ │
│ │ 32-bits and is a 64-bit │ │
│ │ unsigned integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS is │ │
│ │ 64-bits. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│ptrdiff_t │ A signed integer type that │ n/a │
│ │ is the result of subtracting │ │
│ │ two pointers. This is a │ │
│ │ 32-bit signed integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS │ │
│ │ defined in │ │
│ │ clGetDeviceInfo(3clc) is │ │
│ │ 32-bits and is a 64-bit │ │
│ │ signed integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS is │ │
│ │ 64-bits. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│intptr_t │ A signed integer type with │ n/a │
│ │ the property that any valid │ │
│ │ pointer to void can be │ │
│ │ converted to this type, then │ │
│ │ converted back to pointer to │ │
│ │ void, and the result will │ │
│ │ compare equal to the │ │
│ │ original pointer. This is a │ │
│ │ 32-bit signed integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS │ │
│ │ defined in table 4.3 is │ │
│ │ 32-bits and is a 64-bit │ │
│ │ signed integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS is │ │
│ │ 64-bits. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│uintptr_t │ An unsigned integer type │ n/a │
│ │ with the property that any │ │
│ │ valid pointer to void can be │ │
│ │ converted to this type, then │ │
│ │ converted back to pointer to │ │
│ │ void, and the result will │ │
│ │ compare equal to the │ │
│ │ original pointer. This is a │ │
│ │ 32-bit signed integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS │ │
│ │ defined in table 4.3 is │ │
│ │ 32-bits and is a 64-bit │ │
│ │ signed integer if │ │
│ │ CL_DEVICE_ADDRESS_BITS is │ │
│ │ 64-bits. │ │
├───────────────────────────┼──────────────────────────────┼──────────────────────────┤
│void │ The void type comprises an │ void │
│ │ empty set of values; it is │ │
│ │ an incomplete type that │ │
│ │ cannot be completed. │ │
└───────────────────────────┴──────────────────────────────┴──────────────────────────┘
OPTIONAL HALF FLOATING POINT
The half floating-point is supported as an optional extension. An application that wants to use half and
halfn will need to include the cl_khr_fp16(3clc) directive. This will extended the list of built-in
vector and scalar data types to include the following:
┌────────────────────────┬──────────────────────────────┬──────────────────────────┐
│Type in OpenCL Language │ Description │ API type for application │
├────────────────────────┼──────────────────────────────┼──────────────────────────┤
│half2 │ A 2-component half-precision │ cl_half2 │
│ │ floating-point vector. │ │
├────────────────────────┼──────────────────────────────┼──────────────────────────┤
│half3 │ A 3-component half-precision │ cl_half3 │
│ │ floating-point vector. │ │
├────────────────────────┼──────────────────────────────┼──────────────────────────┤
│half4 │ A 4-component half-precision │ cl_half4 │
│ │ floating-point vector. │ │
├────────────────────────┼──────────────────────────────┼──────────────────────────┤
│half8 │ An 8-component │ cl_half8 │
│ │ half-precision │ │
│ │ floating-point vector. │ │
├────────────────────────┼──────────────────────────────┼──────────────────────────┤
│half16 │ A 16-component │ cl_half16 │
│ │ half-precision │ │
│ │ floating-point vector. │ │
└────────────────────────┴──────────────────────────────┴──────────────────────────┘
The relational, equality, logical and logical unary operators can be used with half scalar and halfn
vector types and shall produce a scalar int and vector shortn result respectively.
The OpenCL compiler accepts an h and H suffix on floating point literals, indicating the literal is typed
as a half.
SPECIFICATION
OpenCL Specification[1]
SEE ALSO
macroLimits(3clc), vectorDataTypes(3clc), reservedDataTypes(3clc), otherDataTypes(3clc),
abstractDataTypes(3clc), enums(3clc), cl_khr_fp16(3clc), cl_khr_fp64(3clc)
AUTHORS
The Khronos Group
COPYRIGHT
Copyright © 2007-2011 The Khronos Group Inc.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and/or
associated documentation files (the "Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Materials, and to permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included in all copies or
substantial portions of the Materials.
NOTES
1. OpenCL Specification
page 195, section 6.1.1 - Built-in Scalar Data Types