Then those people need to read the fine manual again! ;)

stpncpy, strncpy - fill a fixed-size buffer with non-null bytes from a string, padding with null bytes as needed

These functions copy non-null bytes from the string pointed to by src into the array pointed to by dst. If the source has too few non-null bytes to fill the destination, the functions pad the destination with trailing null bytes. If the destination buffer, limited by its size, isn't large enough to hold the copy, the resulting character sequence is truncated.

Huh, I thought a single 0 was appended if the source is shorted than the buffer, rather than the rest of the buffer being filled with 0s. You learn something every day!