Append output to a string, according to a format. Never write out of
the destination buffer, and always put a terminating 0 within
the buffer.
@param dst destination buffer (string to which the output is
appended)
@param size total size of the destination buffer
@param fmt printf-compatible format string, specifying how the
following parameters are used
@return the length of the string that would have been generated
if enough space had been available
Append output to a string, according to a format. Never write out of the destination buffer, and always put a terminating 0 within the buffer. @param dst destination buffer (string to which the output is appended) @param size total size of the destination buffer @param fmt printf-compatible format string, specifying how the following parameters are used @return the length of the string that would have been generated if enough space had been available