memcpy

: problem Extension: The immediate consequences of a buffer overflow are generally denial of service, and under certain conditions it can be used to send customized packets to the server to execute custom code, depending on the operating system and compiler's secure compilation options. Solution Recommendations: All external data (network data, command line, environment variables, file contents, etc.) are not trustworthy, in the operation of external data must be strictly filtered, in

First look at a piece of code#include #includeintMain () {intt1[Ten]; inti =0; for(i; iTen; i++) {T1[i]=i; printf ("t1[%d] =%d\n", I, t1[i]); } printf ("\ n"); memcpy (t1[0], t1[2],5*sizeof(int)); I=0; for(i; i5; i++) {printf ("t1[%d] =%d\n", I, t1[i]); } return 0;}I ran the ubuntu16.04, and the output was:t1[02t1[13t1[24t1[3 5 t1[46But the same program runs on ubuntu14.04 's virtual machine, and the result is:t1[02t1[15t1[24t1[3 5 t1[46The copy

#define _CRT_SECURE_NO_WARNINGS1#includeC Language: Analog implementation memcpy

Software projects in the code, fewer than thousands of lines, many tens of thousands of lines, but not irregular to follow. After reading so much code, I found that two functions appear very frequently, and that is the memset () and memcpy () functions, which are often used in C language programming. After work, I looked up some information, and now make a brief description of them. 1. memset () function (1) Function prototype void *memset (void *d

Topic:You define a function to implement the my_memcpy and My_memmove functions.Topic Analysis:The memcpy function mainly implements the memory copy, the function accepts any kind of parameter, and has the limit of the number of copies, the function and the strcpy function have similarities in function and different points. The Memmove function solves the problem of memory overlap based on the memcpy functi

and memcpy:1, copied content, strcpy can only copy strings, and memcpy can copy arbitrary content, for example, character array, type, struct, class, etc.2, the method of copying is different, strcpy does not need to specify the length, it encounters the string Terminator ' \ ' will end. memcpy determines the length of the copy according to its 3rd parameter.3,

Review on that dayCode. About whether memcpy can catch. The Code is as follows. The conclusion is that cacth does not exist. The cause is that memcpy is C and no exception mechanism is implemented... Http://stackoverflow.com/questions/7164019/does-memcpy-not-throw-exceptions // # Include # Include Int Fun(); Int Main() { Return

Related functions: bcopy (), Memccpy (), Memmove (), Strcpy (), strncpy () Header file: # include Define function: void * memcpy (void * DEST, const void * SRC, size_t N) Function Description: memcpy () is used to copy the first n Bytes of memory content in SRC to the memory address in DeST. Unlike strcpy (), memcpy () completely copies n Bytes and does not end w

1. function prototype (c ++ reference) Void * memcpy (void * destination, const void * source, size_t num); some overwriting problems cannot be solved.Char * strcpy (char * destination, const char * source); cannot solve some overwriting problems. '\ 0' indicates that string replication is terminated.Void * memmove (void * destination, const void * source, size_t num); solves all overwriting problems.Void * memset (void * ptr, int value, size_t num);

1. strcpy is a copy string and ends with a/0 mark (that is, once the memory address copy process with a data value of 0 is stopped) The prototype of strcpy is Char * strcpy (char * DEST, const char * SRC) if the Dest space is insufficient, it will cause buffer overflow 2. strncpy to copy n strings, not enough The most common problem with/0 completion is that strncpy does not guarantee that/0 ends. Char Buf [8]; strncpy (BUF, "abcdefgh", 8); read this program, the Buf will be filled with "abcdefg

First, memcpyThe function of the memcpy function is to copy n bytes from the beginning of the memory address referred to by the source SRC to the starting position of the memory address referred to by the target dest.void* my_memcpy (void* dest, const void *SRC, size_t N) {assert (dest); assert (SRC); char* dest_t = (char*) dest;char* src_t = (c har*) Src;while (n--) {*dest_t = *src_t;dest_t++;src_t++;} return dest;}Second, MemmoveMemmove is used to c

Type extraction is a common programming technique designed to implement different types of data to the same function, such as the implementation of cout in STL, which differs from class encapsulation in that we do not know what type of object we call, the type extraction is the compiler knows the type, first implementation, The encapsulation of a class is the first definition of the type, and then the implementation method. Here we can use the special template to implement its programming ideas.

Today in the implementation of the two-dimensional array copy function, there have been a lot of problems, or too careless.We know that the usual matrix replication, is nothing more than a double loop assignment operation, so today want to use memcpy to copy Operations , of course, the copy of one-dimensional array in the previous article has been practicedThe questions to note are:The essence of replication is to use the line + variable byte number *

The following 3 points are the main differences1, the content of the copy is different. strcpy can only copy strings, while memcpy copies arbitrary content, such as character arrays, integers, structs, classes, and so on.2, the method of replication is different. strcpy does not need to specify a length, it encounters the string terminator of the copied character "\" before it ends, so it is prone to overflow. mem