Why is there no std::stou?

c++ string c++11 std
David Stone picture David Stone · Jan 3, 2012 · Viewed 17.3k times · Source

C++11 added some new string conversion functions:

http://en.cppreference.com/w/cpp/string/basic_string/stoul

It includes stoi (string to int), stol (string to long), stoll (string to long long), stoul (string to unsigned long), stoull (string to unsigned long long). Notable in its absence is a stou (string to unsigned) function. Is there some reason it is not needed but all of the others are?

related: No "sto{short, unsigned short}" functions in C++11?

Answer

Kerrek SB picture Kerrek SB · Jan 3, 2012

The most pat answer would be that the C library has no corresponding “strtou”, and the C++11 string functions are all just thinly veiled wrappers around the C library functions: The std::sto* functions mirror strto*, and the std::to_string functions use sprintf.

Edit: As KennyTM points out, both stoi and stol use strtol as the underlying conversion function, but it is still mysterious why while there exists stoul that uses strtoul, there is no corresponding stou.

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