The fflagstostr function returns a comma separated string of the file flags represented by flags. If no flags are set a zero length string is returned.
If memory cannot be allocated for the return value, fflagstostr returns NULL.
The value returned from fflagstostr is obtained from malloc and should be returned to the system with free when the program is done with it.
The strtofflags function takes a string of file flags, as described in chflags(1), parses it, and returns the set flags and clear flags such as would be given as arguments to chflags(2). On success strtofflags returns 0, otherwise it returns non-zero and stringp is left pointing to the offending token.
The fflagstostr function may fail and set errno for any of the errors specified for the library routine malloc(3).
chflags(1), chflags(2), malloc(3)