The array of character data supplied is assumed to hold "nel" adjacent fixed-length strings (without terminating nulls), each of length "len" characters. This function allocates memory and creates a null-terminated copy of each of these strings. It also creates an array of "nel" pointers which point at the start of each of these new strings. A pointer to this index array is returned.
The memory used is allocated in a single block and should later be de-allocated using astFree.
The returned pointer should be passed to astFree to de-allocate the memory used when it is no longer required. This will free both the index array and the memory used by the strings it points at.
AST A Library for Handling World Coordinate Systems in Astronomy