2019年11月27日 · memset treats the target memory region as an array of bytes, not an array of ints. A fairly popular hack for filling a memory region with a repetitive pattern is actually based on memcpy . It critically relies on the expectation that memcpy copies data in forward direction

memset- set bytes in memory. Synopsis-#include<string.h> void *memset(void *s,int c,size_t n) Description- The memset() function shall copy c (converted to an unsigned char) into each of the first n bytes of the object pointed to by s. Here for the above function , the memset() shall return s …

2015年8月12日 · Next, memset sets the memory where the object b was located to certain value, say zero. Now, once our TestStruct object goes out of scope, it is going to be destroyed and when the turn comes to it's member std::string b you'll see a crash, as all of that object's internal structures were ruined by the memset.

2011年12月16日 · memset is likely to be able to write 4 or 8 bytes at a time and/or take advantage of special cache hint instructions; therefore it may well be faster than your byte-at-a-time loop. (NOTE: Some compilers are clever enough to recognize a bulk-clearing loop and substitute either wider writes to memory or a call to memset. Your mileage may vary.

2014年4月13日 · memset(arr, 1, sizeof arr); internally reset all the individual bytes of the memory to 1. For example in 32-bit system: 00000001 00000001 00000001 00000001 = 0x01010101 = 16843009 != 1 (0x00000001)

2015年11月23日 · memset fill memory with constant byte . void *memset(void *s, int c, size_t n); Use of memset is programmer can directly fill memory with particular. and memcpy uses constant void pointer to source which cannot be changed. memcpy copy the memory area. void *memcpy(void *dest, const void *src, size_t n); Reference memcpy memset

2010年3月20日 · Don't use memset. It's a holdover from C and won't work on non-PODs. It's a holdover from C and won't work on non-PODs. Specifically, using it on a derived class that contains any virtual functions -- or any class containing a non-builtin -- will result in disaster.

2019年7月21日 · malloc + memset in that means that you're needlessly zeroing it twice. Use malloc only when it is going to be initialized non-zero. – Antti Haapala -- Слава Україні

2013年6月14日 · memset is a standard C function while bzero has never been a C standard function. The rationale is probably because you can achieve exactly the same functionality using memset function. Now regarding efficiency, compilers like gcc use builtin implementations for memset which switch to a particular implementation when a constant 0 is detected.

2012年10月17日 · std::memset(buffer, 0, sizeof(*buffer) * ARRAY_LENGTH); This code remains correct if the type of buffer changes, provided of course that it continues to have ARRAY_LENGTH elements of whatever type that is, and provided that all-bits-zero remains the correct initial value.