C++11 char16_t strstr and sprintf equivalent

Question

Is there any equivalent function to strstr and sprintf for char16_t type?

Also, where could I find the remaining functions of char16_t?

The UTF-16 equivalent of strstr is [wcsstr](http://www.cplusplus.com/reference/cwchar/wcsstr/). Here is the complete list: http://www.cplusplus.com/reference/cwchar/wcsstr/. And here is a Must-Read link: http://www.joelonsoftware.com/articles/Unicode.html — paulsm4, May 23 '13 at 05:37
Beware: wide char are not UTF-16 on every systems. AFAIK, on Linux `wchar_t` is a 32 bits integral type. — Basile Starynkevitch, May 23 '13 at 05:39
@Basile Starynkevitch - good point. The link I cited tries to make clear that Unicode != UTF-16 != UCS-2 != char16_t (like 1990's era Windows NT or Java programming might have you believe). — paulsm4, May 23 '13 at 05:41
One additional link: http://stackoverflow.com/questions/4588302/why-isnt-wchar-t-widely-used-in-code-for-linux-related-platforms — paulsm4, May 23 '13 at 05:45

Basile Starynkevitch · Accepted Answer · 2013-05-23T12:13:33.407

3

I don't think there are such functions.

If sizeof(char16_t) == sizeof(wchar_t) you could use the wide string functions like wsprintf

^{Caveat: sizeof(wchar_t) == sizeof(int32_t) on Linux!}

And you can always use (in C++11) the std::u16string

Perhaps you might consider using Qt5 QChar (almost like a char16_t in UTF16) and QString. You'll only need to link QtCore for that. Then QString::arg is similar (but not equivalent) to what sprintf can offer.

As I commented, float to string conversion is tricky. Perhaps some code from MUSL libc (free software, MIT license) could inspire you, and you might borrow some of it.

edited May 23 '13 at 12:13

answered May 23 '13 at 05:37

Basile Starynkevitch

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Thanks for the answer. It seems that I can implement strstr out of std::u16string. How to implement sprintf for char16_t out of this? – doptimusprime May 23 '13 at 06:13
But I cannot link QtCore to my project due to some constraints. – doptimusprime May 23 '13 at 08:54
Then you have to re-implement your `sprintf` like function. – Basile Starynkevitch May 23 '13 at 10:42
That is what I did. But due to some limitation, I have not supported %f and %e format because I need floating point or double to string conversion. Can you give me good links to do this accurately? – doptimusprime May 23 '13 at 10:48
1

No, I can't give links; it is tricky and hard to do right. Maybe some code from [MUSL libc](http://musl-libc.org/) could help you (MIT licensed free software). – Basile Starynkevitch May 23 '13 at 11:06

score 0 · Answer 2 · answered Jan 01 '23 at 17:49

For strstr you can use std::u16string_view::find or even the C++23 std::u16string_view::contains if you're only interested in a boolean result.

const bool contains_world =
    std::u16string_view(u"Hello, World!").find(u"World") != std::u16string_view::npos;

C++11 char16_t strstr and sprintf equivalent

2 Answers2