Description

The preprocessing directives defined by the C99 specification are supported.

The #pragma directive is described as:

#pragma pp-tokensopt new-line

A #pragma directive where the preprocessing token OPENCL (used instead of STDC) does not immediately follow pragma in the directive (prior to any macro replacement) causes the implementation to behave in an implementation-defined manner. The behavior might cause translation to fail or cause the translator or the resulting program to behave in a non-conforming manner. Any such pragma that is not recognized by the implementation is ignored. If the preprocessing token OPENCL does immediately follow #pragma in the directive (prior to any macro replacement), then no macro replacement is performed on the directive, and the directive shall have one of the following forms whose meanings are described elsewhere:

// on-off-switch is one of ON, OFF, or DEFAULT
#pragma OPENCL FP_CONTRACT on-off-switch

#pragma OPENCL EXTENSION extensionname : behavior

#pragma OPENCL EXTENSION all : behavior

The following predefined macro names are available.

__FILE__

The presumed name of the current source file (a character string literal).

__LINE__

The presumed line number (within the current source file) of the current source line (an integer constant).

__OPENCL_VERSION__

Substitutes an integer reflecting the version number of the OpenCL supported by the OpenCL device. The version of OpenCL described in this document will have __OPENCL_VERSION__ substitute the integer 200.

CL_VERSION_1_0

Substitutes the integer 100 reflecting the OpenCL 1.0 version.

CL_VERSION_1_1

Substitutes the integer 110 reflecting the OpenCL 1.1 version.

CL_VERSION_1_2

Substitutes the integer 120 reflecting the OpenCL 1.2 version.

CL_VERSION_2_0

Substitutes the integer 200 reflecting the OpenCL 2.0 version.

__OPENCL_C_VERSION__

Substitutes an integer reflecting the OpenCL C version specified by the -cl-std build option (see section 5.8.4.5 of the OpenCL Specification) to clBuildProgram or clCompileProgram. If the -cl-std build option is not specified, the highest OpenCL C 1.x language version supported by each device is used as the version of OpenCL C when compiling the program for each device. The version of OpenCL C described in this document will have __OPENCL_C_VERSION__ substitute the integer 200 if -cl-std=CL2.0 is specified.

__ENDIAN_LITTLE__

Used to determine if the OpenCL device is a little endian architecture or a big endian architecture (an integer constant of 1 if device is little endian and is undefined otherwise). Also refer to the value of the CL_DEVICE_ENDIAN_LITTLE device query.

__kernel_exec(X, type__n__) (and kernel_exec(X, typen)) is defined as

__kernel __attribute__((work_group_size_hint(X, 1, 1))) \
    __attribute__((vec_type_hint(type__n__)))
__IMAGE_SUPPORT__

Used to determine if the OpenCL device supports images. This is an integer constant of 1 if images are supported and is undefined otherwise. Also refer to the value of the CL_DEVICE_IMAGE_SUPPORT device query.

__FAST_RELAXED_MATH__

Used to determine if the -cl-fast-relaxed-math optimization option is specified in build options given to clBuildProgram or clCompileProgram. This is an integer constant of 1 if the -cl-fast-relaxed-math build option is specified and is undefined otherwise.

The NULL macro expands to a null pointer constant. An integer constant expression with the value 0, or such an expression cast to type void * is called a null pointer constant.

The macro names defined by the C99 specification but not currently supported by OpenCL are reserved for future use.

The predefined identifier __func__ is available.

See Also

Document Notes

For more information, see the OpenCL C Specification

This page is extracted from the OpenCL C Specification. Fixes and changes should be made to the Specification, not directly.

Copyright (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.