Dec 28, 2010 · @Simone - libc writers have spend a lot of time making sure their memcpy implementations are efficient, and compiler writers have spent just as much time making their compilers look for cases when assignments could be made faster by memcpy and vice versa. Your argument of "it can be as bad as you want it to" as well as your out-of-the-blue Dec 1, 2022 · If the source and destination regions overlap, the behavior of memcpy_s is undefined. Use memmove_s to handle overlapping regions. These functions validate their parameters. If count is non-zero and dest or src is a null pointer, or destSize is smaller than count, these functions invoke the invalid parameter handler, as described in Parameter Sep 26, 2016 · A good strdup (s) will make one pass and use optimal copy code when the length warrants it. Perhaps by using memcpy () or equivalent. The key is that strdup () is expected to be used often and a library that implements this non-standard C library function is expected to be crafted to perform optimally. Dec 11, 2023 · Strings belong to the standard string class in C++. We can declare strings using the C-style character string or standard string class. The strcpy () function copies one string into another. The strcat () function concatenates two functions. The strlen () function returns the length of a function. Aug 20, 2013 · Description The bcopy () function copies n bytes from src to dest. The result is correct, even when both areas overlap. Conforming to: 4.3BSD, it seems b comes from BSD and it seems deprecated. Which means bcopy is analogous to memmove () not memcpy () as R.. said at his comment. Apr 16, 2020 · The difference between memcpy and memmove is that in memmove, the source memory of specified size is copied into buffer and then moved to destination. So if the memory is overlapping, there are no side effects. in case of memcpy (), there is no extra buffer taken for source memory. Sep 17, 2013 · Now you can do strcat, because the first character of 'stuff' is the null-terminator, so it will append to the right place. In C, you still need to initialize 'stuff', which can be done a couple of ways: char stuff [100]; // not initialized stuff [0] = '\0'; // first character is now the null terminator, // so 'stuff' is effectively "" strcpy Jun 26, 2017 · Common optimization directions for memcpy: Maximize memory/cache bandwidth (vector instruction, instruction-level parallel) Load/store address alignment. Batched sequential access. Use non-temporal access instruction as appropriate. Use the String instruction as appropriate to speed up larger copies. Answer: memcpy () function is is used to copy a specified number of bytes from one memory to another. memmove () function is used to copy a specified number of bytes from one memory to another or to overlap on same memory. Difference between memmove () and memcpy () is, overlap can happen on memmove (). Whereas, memory overlap won’t happen in Sep 5, 2012 · Functions like strcpy() and particularly memcpy() on the other hand, are heavily optimized by the compiler, often implemented in inline assemble for maximum performance. Some measurements I once made on barebone 16-bit low-end microcontrollers are included below. Wxy81.

difference between memcpy and strcpy