Performs the following operations in order:

1. Implicitly creates objects atdest.
2. Copiescount characters (as if of typeunsignedchar, the same below) from the object pointed to bysrc into a temporary arrayarr ofcount characters, wherearr does not overlap the objects pointed to bydest andsrc.
3. Copiescount characters fromarr into the object pointed to bydest.

Ifdest orsrc is anull pointer orinvalid pointer, the behavior is undefined.

[edit]Parameters

[edit]Return value

If there is asuitable created object, returns a pointer to it; otherwise returnsdest.

[edit]Notes

Despite the specification says a temporary buffer is used, actual implementations of this function do not incur the overhead of double copying or extra memory. For smallcount, it may load up and write out registers; for larger blocks, a common approach (glibc and bsd libc) is to copy bytes forwards from the beginning of the buffer if the destination starts before the source, and backwards from the end otherwise, with a fall back tostd::memcpy when there is no overlap at all.

Wherestrict aliasing prohibits examining the same memory as values of two different types,std::memmove may be used to convert the values.

[edit]Example

#include <cstring>#include <iostream> int main(){char str[]="1234567890";std::cout<< str<<'\n';    std::memmove(str+4, str+3,3);// copies from [4, 5, 6] to [5, 6, 7]std::cout<< str<<'\n';}

12345678901234456890

[edit]Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

[edit]See also

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