IsCIdentifier tests for a string that conforms the definition of an identifier in C.

IsDNS1123Label tests for a string that conforms to the definition of a label in DNS (RFC 1123).

IsDNS1123Subdomain tests for a string that conforms to the definition of a subdomain in DNS (RFC 1123).

IsDNS952Label tests for a string that conforms to the definition of a label in DNS (RFC 952).

IsHTTPHeaderName checks that a string conforms to the Go HTTP library's definition of a valid header field name (a stricter subset than RFC7230).

IsValidGroupId tests that the argument is a valid gids.

IsValidIPv4 tests that the argument is a valid IPv4 address.

IsValidPortName check that the argument is valid syntax.

IsValidPortNum tests that the argument is a valid, non-zero port number.

IsValidUserId tests that the argument is a valid uids.