json_decref无法释放内存? [英] json_decref not freeing memory?

问题描述

此问题与C的libjansson JSON API有关.json_decref函数用于跟踪对json_t对象的引用数，并且当引用数达到0时应释放分配的内存.那为什么这个程序会导致内存泄漏呢?我想念什么?仅仅是没有垃圾收集吗?

This question relates to the libjansson JSON API for C. The json_decref function is to be used to keep track of the number of references to a json_t object and when the number of references reaches 0, should free the memory that was allocated. Then why does this program cause a memory leak? What am I missing? Is it just that there is no garbage collection?

int main() {
    json_t *obj;
    long int i;

    while(1) {
        // Create a new json_object
        obj = json_object();

        // Add one key-value pair
        json_object_set(obj, "Key", json_integer(42));

        // Reduce reference count and because there is only one reference so
        // far, this should free the memory.
        json_decref(obj);
    }

    return 0;
}

推荐答案

这是因为json_integer(42)创建的json整数未释放，因此您也需要释放该对象:

It was because the json integer created by json_integer(42) was not freed, you need to free that object too:

int main(void) {
    json_t *obj, *t;
    long int i;

    while(1) {
        // Create a new json_object
        obj = json_object();

        // Add one key-value pair
        t = json_integer(42);
        json_object_set(obj, "Key", t);

        // Reduce reference count and because there is only one reference so
        // far, this should free the memory.
        json_decref(t);
        json_decref(obj);
    }

    return 0;
}

还要注意，main应该是标准的int main(void).

Also note main should be int main(void) by the standard.

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