objective c - What is the assign-enum warning in clang? -

i going through afnetworking implementation , found this

#pragma clang diagnostic push #pragma clang diagnostic ignored "-wassign-enum" [request sethttpbody:[nsjsonserialization datawithjsonobject:parameters options:0 error:&error]]; #pragma clang diagnostic pop 

(afhttpclient:489-492)

the assign-enum warning being turned off, wonder mean.

what warning thrown clang in case?

the warning emitted in absence of clang pragmas is:

integer constant not in range of enumerated type 'nsjsonwritingoptions' (aka 'enum nsjsonwritingoptions')

looking @ declaration of nsjsonwritingoptions, see there no defined value 0:

enum {     nsjsonwritingprettyprinted = (1ul << 0) }; typedef nsuinteger nsjsonwritingoptions; 

the docs suggest passing 0, there no option defined nsjsonwritingnooption = 0, , assigning constant (0) enum type doesn't define 0 possible value.