During kernel execution, printf data is stored in a global printf buffer allocated automatically by the Intel FPGA SDK for OpenCL Offline Compilers.
The size of this buffer is 64 KB, so the total size of the data arguments of the printf call should not exceed this size.
(Reference) FPGA SDK for OpenCL Pro Edition - Programming Guide
A.2.2. OpenCL 1.2 C Programming Language Implementation • FPGA SDK for OpenCL Pro Edition Programming Guide
(Table of Support Statuses of OpenCL 1.2 C Programming Language Features)
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Category: OpenCL
Tools: FPGA SDK for OpenCL™
Devices: -