Fix sample error in docs

[superzscy]

No description provided.

[coveralls]

Pull Request Test Coverage Report for Build 184

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 80.324%

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Totals
Change from base Build 183:	0.0%
Covered Lines:	3172
Relevant Lines:	3949

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💛 - Coveralls

[owent]

Thank you for your patch.But we don't assume user use the c11 standard(which is not default for old GCC & clang even compiling with -std
=c++11 or higher). So we should not use memcpy_s in sample or unit test.

Anyway, there is no need to copy the data block, we can use std::cout.write(reinterpret_cast<const char*>(buffer), length); instead.

I will fix the compile problem and the terminate character of string latter and then put this code into sample project。Still thanks for your contribution.