2011年4月7日 · void * memcpy ( void * destination, const void * source, size_t num ); When you pass in mainbuf, you are passing the same destination address each time. You need to increment the destination address everytime you use memcpy so that it places it in subsequent memory, instead of overwriting the same string each time.

2012年6月13日 · memcpy works on the byte level, but integers are a series of bytes. Depending on your target architecture, the bytes within an integer may be arranged differently (big-endian, little-endian, etc). Using memcpy on integers may or may not do what you expect. It's best to use byte arrays when learning how memcpy and friends work.

2014年11月20日 · memcpy(dst, src, ARRAY_LENGTH*sizeof(int)); or. memcpy(dst, src, sizeof(dst)); Will the second option always work? Regardless of the content? One thing that favors the last one is that if the array were to change, it'll be some house-keeping to …

2015年11月23日 · memcpy() copies from one place to another. memset() just sets all pieces of memory to the same value. Example: memset(str, '*', 50); The above line sets the first 50 characters of the string str to * (or whatever second argument of the memset). memcpy(str2, str1, 50); The above line copies the first 50 characters of str1 to str2.

2016年9月5日 · Please note: memcpy is C, not C++. Although i use it frequently there is no doubt that memcpy in general is in total contrast to major C++ concepts as type safety, inheritance, exceptions. etc. Its very easy to screw up everything with memcpy. –

2013年3月28日 · Raw memcpy(3) does not support it -- compilers are allowed to assume that only valid pointers are passed to it and can optimize away NULL checks after such a call.

2010年5月24日 · where as memcpy copies data (not character) from source to destination of given size n, irrespective of data in source. memcpy should be used if you know well that source contain other than character. for encrypted data or binary data, memcpy is ideal way to go. strcpy is deprecated, so use strncpy.

2013年7月7日 · The implementation of memcpy is highly specific to the system in which it is implemented. Implementations are often hardware-assisted. Implementations are often hardware-assisted. Memory-to-memory mov instructions are not that uncommon - they have been around since at least PDP-11 times, when you could write something like this:

2010年6月3日 · Here is an alternative C version of memcpy that is inlineable and I find it outperforms memcpy for GCC for Arm64 by about 50% in the application I used it for. It is 64-bit platform independent. The tail processing can be removed if the usage instance does not need it for a bit more speed.

2009年12月25日 · Assuming a sane library implementor, memcpy will always be at least as fast as memmove.However, on most platforms the difference will be minimal, and on many platforms memcpy is just an alias for memmove to support legacy code that (incorrectly) calls memcpy on overlapping buffers.