int capng_update(capng_act_t action, capng_type_t type,unsigned int capability);
capng_update will update the internal posix capabilities settings based on the options passed to it. The action should be eith CAPNG_DROP to set the capability bit to 0, or CAPNG_ADD to set the capability bit to 1. The operation is performed on the capability set specified in the type parameter. The values are: CAPNG_EFFECTIVE, CAPNG_PERMITTED, CAPNG_INHERITABLE, CAPNG_BOUNDING_SET. The values may be or'ed together to perform the same operation on multiple sets. The last paramter, capability, is the capability define as given in linux/capability.h.
This returns 0 on success and -1 on failure.