The exact value of iostream synchronizes with ios_base :: sync_with_stdio

Question

It just means what we are doing with the object, since cout is synchronized with stdout (and vice versa?). What does it mean? Is stdio also syncing with stdout?

Answer 1

The default value used by std :: cout and stdio (e.g. printf) is standard, but this is not necessarily the case.

The output can always be redirected to another destination. Referring to this: http://www.tldp.org/LDP/abs/html/io-redirection.html

Answer 2

If synchronization is turned off, in some cases C ++ threads will be faster.

By default, all standard C ++ streams are synchronized with their respective C streams.

Example:

#include <iostream> #include <cstdio> using namespace std; int main() { cout.sync_with_stdio(false); cout << "Hello\n"; printf("World\n"); cout << "...\n"; } 

Output:

 Hello ... World 

Changing true gives the default result. Output:

 Hello World ... 

Answer 3

Per cppreference:

 Sets whether the standard C++ streams are synchronized to the standard C streams after each input/output operation.