decodeInt64forKey

decodeInt64ForKey is a method in the NSCoder family used to read a 64-bit integer value from a keyed archive. It is commonly accessed on encoders and decoders such as NSKeyedUnarchiver and NSCoder and is paired with the corresponding encodeInt64ForKey method when writing data.

In Objective-C, the method signature is typically - (int64_t)decodeInt64ForKey:(NSString *)key;. In Swift, the equivalent is decodeInt64(forKey:) and is called on a coder object, for example coder.decodeInt64(forKey: "counter"). The method returns the Int64 value that was previously encoded under the specified key.

Usage context involves keyed archiving workflows, where data is encoded with a key and later decoded using the same key. It is important that the value for the given key was originally encoded as an Int64; otherwise, decoding may raise an exception or fail to return the expected type. To reduce risk, ensure consistency between encodeInt64(forKey:) and decodeInt64(forKey:), and consider checking for key existence or handling potential decoding errors in your error-handling strategy.

Availability and related concepts: this method is part of the Foundation framework and is used in conjunction with NSKeyedArchiver/NSKeyedUnarchiver for object graphs that support keyed archiving. Related methods include encodeInt64(forKey:), decodeInt32(forKey:), and other typed decode/encode methods provided by NSCoder.