To create a new buffer object (referred to as a sub-buffer object) from an existing buffer object, call the function
cl_mem clCreateSubBuffer( cl_mem buffer, cl_mem_flags flags, cl_buffer_create_type buffer_create_type, const void* buffer_create_info, cl_int* errcode_ret);
buffer must be a valid buffer object and cannot be a sub-buffer object.
flags is a bit-field that is used to specify allocation and usage information about the sub-buffer memory object being created and is described in the Memory Flags table. If the
CL_MEM_WRITE_ONLYvalues are not specified in flags, they are inherited from the corresponding memory access qualifiers associated with buffer. The
CL_MEM_COPY_HOST_PTRvalues cannot be specified in flags but are inherited from the corresponding memory access qualifiers associated with buffer. If
CL_MEM_COPY_HOST_PTRis specified in the memory access qualifier values associated with buffer it does not imply any additional copies when the sub-buffer is created from buffer. If the
CL_MEM_HOST_NO_ACCESSvalues are not specified in flags, they are inherited from the corresponding memory access qualifiers associated with buffer.
buffer_create_type and buffer_create_info describe the type of buffer object to be created. The list of supported values for buffer_create_type and corresponding descriptor that buffer_create_info points to is described in the SubBuffer Attributes table.
Missing before version 1.1.
Create a buffer object that represents a specific region in buffer.
buffer_create_info is a pointer to a https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_API.html#cl_buffer_region structure specifying a region of the buffer.
If buffer is created with
The buffer object returned references the data store allocated for buffer and points to the region specified by buffer_create_info in this data store.
CL_SUCCESS if the function is executed
Otherwise, it returns one of the following errors in errcode_ret:
CL_INVALID_MEM_OBJECTif buffer is not a valid buffer object or is a sub-buffer object.
CL_INVALID_VALUEif buffer was created with
CL_MEM_WRITE_ONLYand flags specifies
CL_MEM_READ_ONLY, or if buffer was created with
CL_MEM_READ_ONLYand flags specifies
CL_MEM_WRITE_ONLY, or if flags specifies
CL_INVALID_VALUEif buffer was created with
CL_MEM_HOST_WRITE_ONLYand flags specify
CL_MEM_HOST_READ_ONLY, or if buffer was created with
CL_MEM_HOST_READ_ONLYand flags specify
CL_MEM_HOST_WRITE_ONLY, or if buffer was created with
CL_MEM_HOST_NO_ACCESSand flags specify
CL_INVALID_VALUEif the value specified in buffer_create_type is not valid.
CL_INVALID_VALUEif value(s) specified in buffer_create_info (for a given buffer_create_type) is not valid or if buffer_create_info is
CL_MEM_OBJECT_ALLOCATION_FAILUREif there is a failure to allocate memory for sub-buffer object.
CL_OUT_OF_RESOURCESif there is a failure to allocate resources required by the OpenCL implementation on the device.
CL_OUT_OF_HOST_MEMORYif there is a failure to allocate resources required by the OpenCL implementation on the host.
CL_INVALID_VALUEif the region specified by the https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_API.html#cl_buffer_region structure passed in buffer_create_info is out of bounds in buffer.
CL_INVALID_BUFFER_SIZEif the size field of the https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_API.html#cl_buffer_region structure passed in buffer_create_info is 0.
CL_MISALIGNED_SUB_BUFFER_OFFSETif there are no devices in context associated with buffer for which the origin field of the https://www.khronos.org/registry/OpenCL/specs/2.2/html/OpenCL_API.html#cl_buffer_region structure passed in buffer_create_info is aligned to the
Concurrent reading from, writing to and copying between both a buffer object and its sub-buffer object(s) is undefined. Concurrent reading from, writing to and copying between overlapping sub-buffer objects created with the same buffer object is undefined. Only reading from both a buffer object and its sub-buffer objects or reading from multiple overlapping sub-buffer objects is defined.
For more information, see the OpenCL Specification
This page is extracted from the OpenCL 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.