Some "safe" languages like Swift and Go offer "unsafe" pointers for use with APIs written in languages like C and Objective-C. Questions using this tag should also have the relevant language tag, e.g. [swift] or [go].
Questions tagged [unsafe-pointers]
250 questions
5
votes
1 answer
Weak/Strong Reference Pointer Relationship
I have been attempting to write my own weak/strong pointer's but I am not clearly understanding the relationship. Everything I seem to come across does not make it and clear and quite often one doc will contridict what another doc says. Could anyone…
chadb
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votes
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Swift 4.1 deinitialize and deallocate(capacity:) deprecated
I've been saying this to form a C array of CGPoint:
let arr = UnsafeMutablePointer.allocate(capacity:4)
defer {
arr.deinitialize()
arr.deallocate(capacity:4)
}
arr[0] = CGPoint(x:0,y:0)
arr[1] = CGPoint(x:50,y:50)
arr[2] =…
matt
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votes
3 answers
A swiftier way to convert String to UnsafePointer in Swift 3 (libxml2)
I'm working on a Swift 3 wrapper for the libxml2 C-library.
There are two convenience methods to convert String to UnsafePointer and vice versa. In libxml2 xmlChar is declared as unsigned char.
UnsafePointer to String is…
vadian
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votes
0 answers
Getting pointer to immutable structure
I'm writing wrapper for some C library. Is it possible to take UnsafePointer to immutable struct? For mutable structs it's not a problem:
func Foo_get(ptr : UnsafePointer) {
//does not mutate
}
struct Foo {
//big data
mutating…
szotp
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5
votes
2 answers
Create a copy of CMSampleBuffer in Swift 2.0
This has been asked before, but something must have changed in Swift since it was asked. I am trying to store CMSampleBuffer objects returned from an AVCaptureSession to be processed later. After some experimentation I discovered that…
Rob
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votes
1 answer
in golang, are unsafe.Pointer()s reference counted?
Are unsafe.Pointer()s reference counted and thus protected from being garbage collected?
As in, if I have a string, it exists while it's in scope, if I have a *string, the string exists while the pointer is in scope, but if I have a…
stu
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1 answer
How to extend String's UnsafePointer initializer to accept NULL pointers?
In Swift, there's a String initialiser that takes an UnsafePointer (or UnsafePointer which is the same I think) as an argument.
However, there's no initialiser that takes an optional UnsafePointer, e.g. a pointer that's NULL (or nil,…
j3141592653589793238
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votes
1 answer
Passing nil as a UnsafePointer
In Swift 2.2, I was able to pass in nil as a valid parameter to a function which requires an UnsafePointer. In Swift 3, I can no longer do that:
func myFuncThatTakesAPointer(buffer: UnsafePointer, length: Int) { /** **/…
JAL
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Swift 3 - Convert c structure sockaddr_in to CFData
I need your help, this code does not compile anymore in Swift 3
//: Let's set up the `sockaddr_in` C structure using the initializer.
var sin = sockaddr_in(
sin_len: UInt8(sizeof(sockaddr_in)),
sin_family: sa_family_t(AF_INET),
sin_port:…
Alexandre Giguere
- 63
- 9
4
votes
1 answer
Swift error: '&' used with non-inout argument of type 'UnsafeMutablePointer'
I'm trying to convert the following Objective-C code (source) from this
-(CGRect) dimensionsForAttributedString: (NSAttributedString *) asp {
CGFloat ascent = 0, descent = 0, width = 0;
CTLineRef line = CTLineCreateWithAttributedString(…
Suragch
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votes
4 answers
Why string pointer position is different?
Why string pointer position is different each time I ran the application, when I'm using StringBuilder but same when I declare a variable?
void Main()
{
string str_01 = "my string";
string str_02 = GetString();
unsafe
{
…
Mohamad Shiralizadeh
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votes
13 answers
Should I rewrite my DSP routines in C/C++ or I'm good with C# unsafe pointers?
I'm currently writing a C# application that does a lot of digital signal processing, which involves a lot of small fine-tuned memory xfer operations. I wrote these routines using unsafe pointers and they seem to perform much better than I first…
Trap
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votes
2 answers
Swift array address is not same as &array[0]
Document said:
An in-out expression that contains a mutable variable, property, or subscript reference of type Type, which is passed as a pointer to the address of the left-hand side identifier.
A [Type] value, which is passed as a pointer to the…
Kk Shinkai
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3 answers
How do I convert an array of UnsafeMutablePointer to an array of Double?
I have created an array like this
var outputReal = UnsafeMutablePointer.allocate(capacity: numeroDados)
Now I need to convert that to an array of Double.
I can convert that using something like this:
var newArray : [Double] = []
for i in…
Duck
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votes
1 answer
(*C.uchar)(&buffer[0]) vs (*C.uchar)(unsafe.Pointer(&buffer[0]))
We have a discussion here over using (or not) unsafe.Pointer for passing pointers to byte arrays from Go to C.
What is the biggest reason (not) to use unsafe.Pointer() ? I would take consistency as a reason, as you'd call an 'external' function,…
Diamondo25
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