c - "malloc"ed 内存是否被隐式释放？

Question

考虑使用 malloc 定义的 (char *) 变量 sTmp，

如果我将另一个变量分配给此 sTmp，通过该变量分配的内存是否会自动释放，或者该内存块是否会保持分配(且无用)直到进程结束？

让我用代码来解释一下:

int main () {
    char *sTmp = (char *) malloc (50);
    char *sNew = strdup ("some text"); // length is less than 50
    sTmp = sNew;
    /*  now sTmp points to sNew and it's length is 10 chars
        I wonder, what happened to the allocated memory of 50 chars in the first line;
        Does it get freed implicitly or remain allocated?
    */
}

Answer 1

Does “malloc”ed memory get freed implicitly?

不，C 中没有垃圾收集器机制。

您必须显式释放使用malloc分配的内存

sTmp = sNew;

此赋值语句会导致内存泄漏，请在赋值之前释放对象。