Provided by: opencl-1.2-man-doc_1.0~svn33624-1_all 
NAME
barrier - All work-items in a work-group executing the kernel on a processor must execute this function
before any are allowed to continue execution beyond the barrier.
void barrier(cl_mem_fence_flags flags);
DESCRIPTION
All work-items in a work-group executing the kernel on a processor must execute this function before any
are allowed to continue execution beyond the barrier. This function must be encountered by all work-items
in a work-group executing the kernel.
If barrier is inside a conditional statement, then all work-items must enter the conditional if any
work-item enters the conditional statement and executes the barrier.
If barrier is inside a loop, all work-items must execute the barrier for each iteration of the loop
before any are allowed to continue execution beyond the barrier.
The barrier function also queues a memory fence (reads and writes) to ensure correct ordering of memory
operations to local or global memory.
The flags argument specifies the memory address space and can be set to a combination of the following
literal values.
CLK_LOCAL_MEM_FENCE - The barrier function will either flush any variables stored in local memory or
queue a memory fence to ensure correct ordering of memory operations to local memory.
CLK_GLOBAL_MEM_FENCE - The barrier function will queue a memory fence to ensure correct ordering of
memory operations to global memory. This can be useful when work-items, for example, write to buffer or
image objects and then want to read the updated data.
SPECIFICATION
OpenCL Specification[1]
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 274, section 6.12.8 - Synchronization Functions