withUnsafeBytes(of:_:)
Invokes the given closure with a buffer pointer covering the raw bytes of the given argument.
Declaration
func withUnsafeBytes<T, E, Result>(of value: borrowing T, _ body: (UnsafeRawBufferPointer) throws(E) -> Result) throws(E) -> Result where E : Error, T : ~Copyable, Result : ~CopyableParameters
- value:
An instance to temporarily access through a raw buffer pointer.
- body:
A closure that takes a raw buffer pointer to the bytes of
valueas its sole argument. If the closure has a return value, that value is also used as the return value of thewithUnsafeBytes(of:_:)function. The buffer pointer argument is valid only for the duration of the closure’s execution. It is undefined behavior to attempt to mutate through the pointer by conversion toUnsafeMutableRawBufferPointeror any other mutable pointer type. If you want to mutate a value by writing through a pointer, usewithUnsafeMutableBytes(of:_:)instead.
Return Value
The return value, if any, of the body closure.
Discussion
The buffer pointer argument to the body closure provides a collection interface to the raw bytes of value. The buffer is the size of the instance passed as value and does not include any remote storage.