buffer not terminated, parse_config.c

parse_config.c, warning:

285 case 's':

CID 208901 (#1 of 1): Buffer not null terminated (BUFFER_SIZE_WARNING)
41. buffer_size_warning: Calling strncpy with a maximum size argument of 20 bytes on destination array configp->shape_func of size 20 bytes might leave the destination string unterminated.

286 strncpy(configp->shape_func, optarg,
287 sizeof(configp->shape_func));