The unordered_map container has a reserve method because it is implemented using buckets, and not a tree as in map. A bucket is: a slot in the container’s internal hash table to which elements are assigned based on the hash value of their key. Buckets are numbered from 0 to (bucket_count-1). (source) A single bucket … Read more
You’re passing an int to this overloaded function. Although human intuition says that ambig(signed long) ought to be preferred because your input is a negative integer (which cannot be represented as such by an unsigned long), the two conversions are in fact equivalent in “precedence” in C++. That is, the conversion int → unsigned long … Read more
Why not just #include the generated headers created from #import?
Two things: The indentation is actually fine, although nowadays unusual (and I personally hate it): they use an indentation of four, which is achieved via spaces, but use tabs for all multiples of eight. This used to be the standard almost everywhere (notably it’s still the default setting in several editors such as Vim). But … Read more
My guess is that this is compiler dependent. However, throwing an exception in the callback would be a very bad idea. Either it will flat-out not work, or the C code in the SQLite library will be unable to handle it. Consider if this is some code in SQLite: { char * p = malloc( … Read more
The the solution/VS version matrix is: VS 6.0 -> 6.0 VS 2002 -> 7.0 VS 2003 -> 8.0 VS 2005 -> 9.0 VS 2008 -> 10.0 VS 2010 -> 11.0 VS 2012 -> 12.0 VS 2013 -> 10.0 to 12.0 VS 2015 -> 10.0 to 14.0 VS 2017 -> 10.0 to 15.0 VS 2019 -> … Read more
Visual C++ allows you to define several ways of setting up precompiled header files. The most common is to enable it for ALL source files at the project configuration level, Under Configuration Properties/C++/Precompiled Headers, setting “Precompiled Header”, select “Use”. The same location, setting “Precompiled Header File”, is usually “stdafx.h”. All files will get this setting … Read more
Same way 32-bit arithmetic worked on 16-bit systems. In this case, it uses 2 32-bit memory addresses to form a 64-bit number together. Addition/substraction is easy, you do it by parts, the only gotcha is taking the carry-over from the lower part to the higher part. For multiplication/division, it’s harder (ie more instructions). It’s obviously … Read more
There is a ton of code out there using MFC. I see these questions all the time is this still used is that still used the answer is yes. I work in a very large organization which still employs hundreds of people who write in cobol. If it has ever been used in the enterprise … Read more
If we can find one example where it does, the answer to your question is “yes”. #include <stdio.h> #include <stdlib.h> int main(int argc, char* argv[]) { unsigned int i; for(i = 0; ; i++) { int r = rand(); if (r == rand()) { printf(“Oops. rand() = %d; i = %d\n”, r, i); break; } … Read more