如何将 NSString 转换为 UTF-8 以外的编码？

Question

I'm working with c in iOS Project I'm trying to convert my string to respected type in c, below code is supposed to send to core Library

typedef uint16_t    UniCharT;
static const UniCharT s_learnWord[] = {'H', 'e','l','\0'};

what i have done till now is string is the one what I'm passing

NSString * string = @"Hel";
static const UniCharT *a = (UniCharT *)[string UTF8String];

But it is failing to convert when more than one character, If i pass one character then working fine please let me where i miss, How can i pass like s_learnWord?

and i tried in google and StackOverFLow none of the duplicates or answers didn't worked for me like this Convert NSString into char array I'm already doing same way only.

Answer 1

Your question is a little ambiguous as the title says "c type char[]" but your code uses typedef uint16_t UniCharT; which is contradictory.

For any string conversions other than UTF-8, you normally want to use the method getCString:maxLength:encoding: .

As you are using uint16_t , you probably are trying to use UTF-16? You'll want to pass NSUTF16StringEncoding as the encoding constant in that case. (Or possibly NSUTF16BigEndianStringEncoding / NSUTF16LittleEndianStringEncoding )

Something like this should work:

include <stdlib.h>

// ...

NSString * string = @"part";
NSUInteger stringBytes = [string maximumLengthOfBytesUsingEncoding];
stringBytes += sizeof(UniCharT); // make space for \0 termination
UniCharT* convertedString = calloc(1, stringBytes);
[string getCString:(char*)convertedString
         maxLength:stringBytes
          encoding:NSUTF16StringEncoding];

// now use convertedString, pass it to library etc.

free(convertedString);