Question

I am working an existing iPhone app, while need to change the code of C.

I want to use a dictionary in standard C file, simpily, I can not use NSDictionary, compiler said it is invalid in c99(coz the headers Foundation/Foundation.h and Foundation/NSDictionary.h can not be found), but CFDictionaryRef is available (coz header CoreFoundation/CoreFoundation.h can be found and imported). Then I try to work with CFDictionary, I can not insert the key-value pairs into the dictionary, could any one take a while and have a look at following code? Thanks in advance!!

ps, the output of following code are:

Dict size: 0
Key: text.html, value: 111

which means the key-value pair is not inserted…

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CFMutableDictionaryRef dict = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);

printf("Dict size: %d\n", (int)((CFIndex)CFDictionaryGetCount(dict)));

int i = 111;
char c[] = "text.html";

const void *key = &c;
const void *value = &i;

printf("Key: %s, value: %d\n", key, *(int *)value);

CFDictionarySetValue(dict, key, value); 

printf("Added\n");

printf("Dict size: %d\n", (int)((CFIndex)CFDictionaryGetCount(dict)));

value = (int *)CFDictionaryGetValue(dict, key);

printf("Value:  %d\n", *(int *)value);

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Thanks for your inputs, following are the working code.

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//init dict
CFMutableDictionaryRef dict = CFDictionaryCreateMutable(NULL, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);

    //insert key-value
int i = 111;
const void *value = &i;
CFDictionaryAddValue(dict, CFSTR("text.html"), CFNumberCreate(NULL, kCFNumberSInt32Type, value));
CFNumberRef valueRef = CFDictionaryGetValue(dict, CFSTR("text.html"));

    //get value based on key
int valuePtr;
CFNumberGetValue(valueRef, kCFNumberSInt32Type, (void *)&valuePtr);
    printf("value: %d\n", valuePtr);

Answer 1

A CFMutableDictionaryRef created with &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks as arguments expects Core Foundation types as keys and values because it will try to retain/release them (using CFRetain/CFRelease).

You should work with CFStringRef and CFNumberRef instead of the plain C types (or alternatively, specify other keyCallBacks and valueCallBacks, possibly NULL).