Converting NSString to std::string

Question

I try to pass a NSString to a C++ function, but I only get the first letter. Here is the code:

#import <Foundation/Foundation.h>
#import <string>
int main(int argc, const char * argv[])
{

@autoreleasepool {
    NSString* objcString=@"test";
    std::string cppString([objcString cStringUsingEncoding:NSUnicodeStringEncoding]);
    NSLog(@"%@, %s",objcString, cppString.c_str()
          );

}
return 0;
}

It gives me:

2013-03-05 10:22:15.362 TEST[1136:353] test, t

Thank for your time, have a good day.

score 2 · Accepted Answer · answered Mar 05 '13 at 15:37

2

The encoding is wrong. NSUnicodeStringEncoding returns an UTF-16 string. The characters "t, e, s, t" fit in one byte - so in UTF-16, they're represented by a non-zero byte and a zero byte. The zero tells NSLog() that it's the end of the string. Use NSUTF8StringEncoding instead.

answered Mar 05 '13 at 15:37

But so how can I do if I want to use exotic character as 'é'? – impact27 Mar 05 '13 at 15:56
@user1987722 The same. UTF-8 ain't ASCII. – Mar 05 '13 at 15:57
Thanks a lot! this is very helpful – impact27 Mar 05 '13 at 16:33

score 1 · Answer 2 · answered Mar 05 '13 at 15:33

1

How about:

std::string cppString([objcString UTF8String]);

answered Mar 05 '13 at 15:33

trojanfoe

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score 0 · Answer 3 · answered Mar 05 '13 at 15:34

0

I do it ubiquitously in my code with NSUTF8Encoding instead that NSUnicodeEncoding.

answered Mar 05 '13 at 15:34

Jack

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score 0 · Answer 4 · edited May 23 '17 at 11:50

0

I think this answer might help you: How do I convert a NSString into a std::string?

For integrity:

NSString *foo = @"Foo";
std::string *bar = new std::string([foo UTF8String]);

edited May 23 '17 at 11:50

Community

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answered Mar 05 '13 at 15:35

o15a3d4l11s2

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Converting NSString to std::string

4 Answers4