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