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cJSON_Print memory leak #764

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earlysun030201 opened this issue Jun 10, 2023 · 1 comment
Closed

cJSON_Print memory leak #764

earlysun030201 opened this issue Jun 10, 2023 · 1 comment

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@earlysun030201
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earlysun030201 commented Jun 10, 2023 •
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I'm using the latest version of the cJSON library, and when I calling cJSON_Print, it results in a memory leak.
C 17 Standard:

extern "C" {
#include "cJSON/cJSON.h"
}
#include <iostream>

int main() {
    while (getchar() == 10) {
        cJSON* json = cJSON_Parse(R"({
        "name": "test",
        "available":    true
        })");
        std::cout << cJSON_Print(json) << std::endl;
        cJSON_Delete(json);
    }
    return 0;
}

image
In the memory viewer, it can be observed that a new instance is created every time the contents within the loop are called.
image
When I remove the invocation of the cJSON_Print function, this issue disappears.
@7aman
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7aman commented Jun 11, 2023

cJSON_Print returns a heap allocated string (null terminated character array). it must be freed later.

extern "C" {
#include "cJSON/cJSON.h"
}
#include <iostream>

int main() {
    while (getchar() == 10) {
        cJSON* json = cJSON_Parse(R"({
        "name": "test",
        "available":    true
        })");
        char *json_str = cJSON_Print(json);
        cJSON_Delete(json);
        std::cout << json_str << std::endl;
       free( json_str );       
    }
    return 0;
}

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@7aman @earlysun030201