CAP_CLEAR(3)               Linux Programmer's Manual              CAP_CLEAR(3)

       cap_clear, cap_clear_flag, cap_get_flag, cap_set_flag, cap_compare -
       capability data object manipulation

       #include <sys/capability.h>

       int cap_clear(cap_t cap_p);

       int cap_clear_flag(cap_t cap_p, cap_flag_t flag);

       int cap_get_flag(cap_t cap_p, cap_value_t cap,
                        cap_flag_t flag, cap_flag_value_t *value_p);

       int cap_set_flag(cap_t cap_p, cap_flag_t flag, int ncap,
                        const cap_value_t *caps, cap_flag_value_t value);

       int cap_compare(cap_t cap_a, cap_t cap_b);

       Link with -lcap.

       These functions work on a capability state held in working storage.  A
       cap_t holds information about the capabilities in each of the three
       sets, Permitted, Inheritable, and Effective.  Each capability in a set
       may be clear (disabled, 0) or set (enabled, 1).

       These functions work with the following data types:

       cap_value_t       identifies a capability, such as CAP_CHOWN.

       cap_flag_t        identifies one of the three flags associated with a
                         capability (i.e., it identifies one of the three
                         capability sets).  Valid values for this type are

       cap_flag_value_t  identifies the setting of a particular capability
                         flag (i.e, the value of a capability in a set).
                         Valid values for this type are CAP_CLEAR (0) or
                         CAP_SET (1).

       cap_clear() initializes the capability state in working storage
       identified by cap_p so that all capability flags are cleared.

       cap_clear_flag() clears all of the capabilities of the specified
       capability flag, flag.

       cap_get_flag() obtains the current value of the capability flag, flag,
       of the capability, cap, from the capability state identified by cap_p
       and places it in the location pointed to by value_p.

       cap_set_flag() sets the flag, flag, of each capability in the array
       caps in the capability state identified by cap_p to value.  The
       argument, ncap, is used to specify the number of capabilities in the
       array, caps.

       cap_compare() compares two full capability sets and, in the spirit of
       memcmp(), returns zero if the two capability sets are identical. A
       positive return value, status, indicates there is a difference between
       them. The returned value carries further information about which of
       three sets, cap_flag_t flag, differ. Specifically, the macro
       CAP_DIFFERS (status, flag) evaluates to non-zero if the returned status
       differs in its flag components.

       cap_clear(), cap_clear_flag(), cap_get_flag() cap_set_flag() and
       cap_compare() return zero on success, and -1 on failure. Other return
       values for cap_compare() are described above.

       On failure, errno is set to EINVAL, indicating that one of the
       arguments is invalid.

       These functions are as per the withdrawn POSIX.1e draft specification.
       cap_clear_flag() and cap_compare() are Linux extensions.

       libcap(3), cap_copy_ext(3), cap_from_text(3), cap_get_file(3),
       cap_get_proc(3), cap_init(3), capabilities(7)

                                  2008-05-11                      CAP_CLEAR(3)