Write the specified length characters at the specified address s to this buffer. Return the number of characters written, which is either length or the distance from the current write position to the end of the write buffer, whichever is smaller, and move the write cursor position by this amount.
Declared in <bdlsb_fixedmemoutput.h>
std::streamsize
sputn(
char const* s,
std::streamsize length);