Apple NSURL网络错误码

/*!
@enum NSURL-related Error Codes
@abstract Constants used by NSError to indicate errors in the WebFoundation domain
@discussion Documentation on each constant forthcoming.
*/
enum
{
NSURLErrorUnknown = -1,
NSURLErrorCancelled = kCFURLErrorCancelled,
NSURLErrorBadURL = kCFURLErrorBadURL,
NSURLErrorTimedOut = kCFURLErrorTimedOut,
NSURLErrorUnsupportedURL = kCFURLErrorUnsupportedURL,
NSURLErrorCannotFindHost = kCFURLErrorCannotFindHost,
NSURLErrorCannotConnectToHost = kCFURLErrorCannotConnectToHost,
NSURLErrorNetworkConnectionLost = kCFURLErrorNetworkConnectionLost,
NSURLErrorDNSLookupFailed = kCFURLErrorDNSLookupFailed,
NSURLErrorHTTPTooManyRedirects = kCFURLErrorHTTPTooManyRedirects,
NSURLErrorResourceUnavailable = kCFURLErrorResourceUnavailable,
NSURLErrorNotConnectedToInternet = kCFURLErrorNotConnectedToInternet,
NSURLErrorRedirectToNonExistentLocation = kCFURLErrorRedirectToNonExistentLocation,
NSURLErrorBadServerResponse = kCFURLErrorBadServerResponse,
NSURLErrorUserCancelledAuthentication = kCFURLErrorUserCancelledAuthentication,
NSURLErrorUserAuthenticationRequired = kCFURLErrorUserAuthenticationRequired,
NSURLErrorZeroByteResource = kCFURLErrorZeroByteResource,
NSURLErrorCannotDecodeRawData = kCFURLErrorCannotDecodeRawData,
NSURLErrorCannotDecodeContentData = kCFURLErrorCannotDecodeContentData,
NSURLErrorCannotParseResponse = kCFURLErrorCannotParseResponse,
NSURLErrorFileDoesNotExist = kCFURLErrorFileDoesNotExist,
NSURLErrorFileIsDirectory = kCFURLErrorFileIsDirectory,
NSURLErrorNoPermissionsToReadFile = kCFURLErrorNoPermissionsToReadFile,
NSURLErrorDataLengthExceedsMaximum NS_ENUM_AVAILABLE(10_5, 2_0) = kCFURLErrorDataLengthExceedsMaximum,

// SSL errors
NSURLErrorSecureConnectionFailed = kCFURLErrorSecureConnectionFailed,
NSURLErrorServerCertificateHasBadDate = kCFURLErrorServerCertificateHasBadDate,
NSURLErrorServerCertificateUntrusted = kCFURLErrorServerCertificateUntrusted,
NSURLErrorServerCertificateHasUnknownRoot = kCFURLErrorServerCertificateHasUnknownRoot,
NSURLErrorServerCertificateNotYetValid = kCFURLErrorServerCertificateNotYetValid,
NSURLErrorClientCertificateRejected = kCFURLErrorClientCertificateRejected,
NSURLErrorClientCertificateRequired = kCFURLErrorClientCertificateRequired,
NSURLErrorCannotLoadFromNetwork = kCFURLErrorCannotLoadFromNetwork,

// Download and file I/O errors
NSURLErrorCannotCreateFile = kCFURLErrorCannotCreateFile,
NSURLErrorCannotOpenFile = kCFURLErrorCannotOpenFile,
NSURLErrorCannotCloseFile = kCFURLErrorCannotCloseFile,
NSURLErrorCannotWriteToFile = kCFURLErrorCannotWriteToFile,
NSURLErrorCannotRemoveFile = kCFURLErrorCannotRemoveFile,
NSURLErrorCannotMoveFile = kCFURLErrorCannotMoveFile,
NSURLErrorDownloadDecodingFailedMidStream = kCFURLErrorDownloadDecodingFailedMidStream,
NSURLErrorDownloadDecodingFailedToComplete =kCFURLErrorDownloadDecodingFailedToComplete,

NSURLErrorInternationalRoamingOff NS_ENUM_AVAILABLE(10_7, 3_0) = kCFURLErrorInternationalRoamingOff,
NSURLErrorCallIsActive NS_ENUM_AVAILABLE(10_7, 3_0) = kCFURLErrorCallIsActive,
NSURLErrorDataNotAllowed NS_ENUM_AVAILABLE(10_7, 3_0) = kCFURLErrorDataNotAllowed,
NSURLErrorRequestBodyStreamExhausted NS_ENUM_AVAILABLE(10_7, 3_0) = kCFURLErrorRequestBodyStreamExhausted,

NSURLErrorBackgroundSessionRequiresSharedContainer NS_ENUM_AVAILABLE(10_10, 8_0) = -995,
NSURLErrorBackgroundSessionInUseByAnotherProcess NS_ENUM_AVAILABLE(10_10, 8_0) = -996,
NSURLErrorBackgroundSessionWasDisconnected NS_ENUM_AVAILABLE(10_10, 8_0)= -997,
};