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memcpy vs assignment in C

I wanted to know if there is a gain in performance of assigning a big structure (e.g 100 bytes) automatic variable to zero rather than doing memset it to zero in run time in C. Not sure if gcc compiler can do optimization at compile time for this

以下是2起案件。

<><>Case 1:

void fun1()
{
   struct S y = {0};
}

<><>Case2:

void fun1()
{
  struct S y;
  memset(&y, 0, sizeof(y));
}

Answer 1

g 几乎肯定会比你更妥善地处理这个问题,这很可能不是你系统业绩的瓶颈,因此,你对努力优化这项工作感到担忧。

Answer 2

这几乎是memcpy vssign in C 。

指派几乎总是比直接篡改记忆(更不用说更确切)。法典毕竟是要读的,而不仅仅是写的。

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