Most active questions
4,189 questions from the last 7 days
14
votes
3
answers
2k
views
Why is it ok to cast to an undeclared struct pointer in C?
Why does this code compile? struct test is not even forward declared.
int main(){
*(int*)((struct test*) 0x1234) = 0x0;
return 0;
}
- 3,038
13
votes
1
answer
1k
views
Is it safe to catch stack overflows? Can it leave objects in messy/intermediate states?
I've been reviewing ways to kill threads in Java, and the overwhelming conclusion is that it is never safe to stop code at arbitrary points - doing so may leave resources in messy intermediate states. ...
- 4,276
11
votes
1
answer
570
views
MSVC calls wrong virtual method when storing a pointer to virtual method in a static inline variable
I'm encountering unexpected behavior on MSVC when storing a pointer to a virtual method in a static inline variable. The issue does not occur on GCC or Clang.
Specifically, when I store a pointer to a ...
- 2,079
4
votes
5
answers
118
views
Assign a number for every matching value in list
I have a long list of items that I want to assign a number to that increases by one every time the value in the list changes. Basically I want to categorize the values in the list.
It can be assumed ...
- 109
9
votes
1
answer
260
views
What explains pattern matching in python not matching for 0.0, but matching for float()?
I would like to understand how pattern matching works in python. When I use matching with a type like float(), it matches 12.0, but when I use it with 0.0, it doesn't. I wonder why.
I am new to ...
- 2,620
6
votes
1
answer
175
views
Assignment in (else) if statement triggers warning in MSVC but not in gcc / clang
This code snippet triggers a warning in MSVC (VS2022 17.10.2).
int m = 0;
if(int i = m)
// ...
else if (int i = m) // warning C4456: declaration of 'i' hides previous local declaration
// ...
...
- 71
10
votes
1
answer
235
views
Why can this C++ code pass compile check? [duplicate]
I accidentally added a semicolon in an expression constructing std::string, but the compiler happily accepted it without complaining anything.
I did a minimum reproducible example below, kindly teach ...
- 1,379
1
vote
4
answers
246
views
std::vector: when is a pointer not a pointer?
I have this existing working code, which I am trying to convert to implementation:
Bitmap *pbitmap = new Bitmap(L"images.png");
nWidth = pbitmap->GetWidth();
nHeight = pbitmap->...
- 69
3
votes
2
answers
102
views
C++: `if constexpr` and `std::is_same_v` not working
I'm playing around with templates, compile-time evaluation and pointers to members.
I don't understand why the following code doesn't set a.x to 42 and a.y to 3.14. According to the output, FieldType ...
- 3,113
20
votes
1
answer
1k
views
CoreWCF stream continues to be written to after client disconnects
I have a very simple service class:
using System.Diagnostics;
var builder = WebApplication.CreateBuilder();
builder.Services.AddServiceModelServices();
builder.Services.AddServiceModelMetadata();
...
- 2,025
3
votes
3
answers
127
views
How do you convert a single surrogate character without a pair into its UTF-8 equivalent?
I am experimenting with wctomb in order to convert a wchar_t into its UTF-8 equivalent stored in a char[]. It works nicely, but not for surrogate characters ranging U+D800 to U+DFFF.
int ret;
// null-...
- 654
0
votes
2
answers
177
views
Invalid comparator in std::sort due to correct same result in both orders
I'm sorting a vector of structs, std::vector<DRIVE_OR_DIR>, where DRIVE_OR_DIR is defined as
typedef struct {
std::string path;
boolean isDrive;
} DRIVE_OR_DIR
The idea is that elements ...
- 12.2k
2
votes
2
answers
201
views
Loop on objects of different types
Consider this code (there are many more ReadJSONkey lines in the real code):
int LoadParametersFromJSON(JsonDocument& JsonDoc)
{
int err = 0;
err += ReadJSONkey(Pins, JsonDoc, "Pins&...
- 23
1
vote
2
answers
164
views
How to declare static constexpr variable in C++?
I have a Foo class that includes an array and a static constexpr variable. As a general convention, I want to write public and private variables respectively. But, compiler error occurs 's_array_size' ...
- 127
2
votes
4
answers
89
views
How to functionalize base R function like `with()`?
I am trying to write a function that operates similarly to with() where the function has a data argument, and two other arguments that I would like evaluated in the context of the data frame.
I ...
- 12.2k