The solution of memcpy memory overlap

Memory region overlap refers to memory region  [src, src+count) And memory area  [dst, dst+count) There is overlap .

memcpy Just a simple copy from front to back , Memory overlap is not considered , If memory overlaps , Its behavior is uncertain .
memmove() Function in memcpy() Function is added to the memory overlap copy processing ; This paper introduces the method of reverse copy to deal with some cases of memory overlap ; Make sure the copy is correct ;

Generally speaking , If you can make sure that the copy memory does not overlap , use  memcpy Than using  memmove More efficient , If there is overlap , You can only use  memmove

ref：

memmove and memcpy And dealing with memory overlap _ Code City blog -CSDN Blog _memcpy Memory overlap

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memcpy Solution of memory overlap - wangicter The blog of - Blog Garden

memcpy Solution of memory overlap - CodeAntenna