Can memcpy given value as source address in c
WebFeb 16, 2013 · As such, it has no address which could be given as parameter to memcpy or another function that expects a memory location. If you want to do this, you need to have a real constant (such as const int ), as suggested in the other answers. WebApr 8, 2024 · Also remember that argument in C are passed by value, meaning the value is copied into the argument variable. Modifying the argument variable (like assigning to it) …
Can memcpy given value as source address in c
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WebThe C library function void *memcpy (void *dest, const void *src, size_t n) copies n characters from memory area src to memory area dest. Declaration Following is the … WebJun 4, 2013 · I need a function that stores data into a void pointer. Here is a simple example of it: void saveData (void* data) { char inputData [] = "some data"; memcpy ( (char*)data, inputData, sizeof (inputData)); } However I get segmentation errors when I do this, even though it compiles just fine. My function argument has to be a void pointer because I ...
WebFeb 16, 2013 · Your constant (macro) is really just a literal. As such, it has no address which could be given as parameter to memcpy or another function that expects a …
WebOct 21, 2014 · But memcpy () is about copying memory objects, not values. An object resides at a given address, and contains a given value. Taking n gives the value, … WebNov 3, 2012 · First, memcpy () doesn't succeed or fail in the normal sense. It just copies the data, which might cause a fault/exception if it reads outside the source array or writes outside the destination array, and it might also read or write outside one of those arrays without causing any fault/exception and just silently corrupting data.
WebJul 11, 2013 · Understanding the source code of memcpy () 00018 void *memcpy (void *dst, const void *src, size_t len) 00019 { 00020 size_t i; 00021 00022 /* 00023 * memcpy …
WebMar 18, 2016 · C standard library often supports this technique, memcpy being another example. A possible use case might be something along the lines of char *clone_buffer (const char *buffer, size_t size) { return memcpy (new char [size], buffer, size); } If memcpy did not return the destination buffer pointer, we'd probably have to implement the above as cute diy christmas decorationsWebJan 21, 2016 · Define you own memcpy to copy to this address space : void my_memcpy( ptr8 addr_dest, const void * src, int len ) { memcpy( my_destination_memory + … cute diy birthday gifts for your momWebOct 25, 2015 · Save it to a .c file, like test.c, and compile it using gcc, like this: It will (most likely) behave differently. Try replacing memcpy with strncpy and see what happen. I hope the example is useful. With memcpy, the destination cannot overlap the source at all. With memmove it can. cheap art supplies online storeWebSo the answer is no; the check is not necessary (or yes; you can pass zero). Share Improve this answer Follow edited Sep 22, 2012 at 10:42 answered Sep 20, 2010 at 13:32 Mike Seymour 248k 28 442 637 1 Would a pointer be considered "valid" for purposes of such a function if it pointed to the location following the last element of an array? cute diy christmas room decorWebApr 17, 2012 · I am trying to read two integers, stored consecutively, from a memory block (i have a pointer void *block pointing to the contents of the block) using memcpy. The first one is read just fine using: memcpy (&test, block, sizeof (int)); I try to read the second using: memcpy (&test, block + sizeof (int), sizeof (int)); (Of course i am having ... cute diy christmas gifts for boyfriendWebOct 11, 2024 · When you refer to the address of a pointer, this normally means the pointer's own location in memory, not the value it holds (which also is an address). – Andreas Wenzel Oct 11, 2024 at 4:55 1 @N001: If you follow the advice I gave in my first comment, does your program then work as intended? Both printed pointer values are the same, then. cute diy christmas gifts for friendsWebOct 3, 2024 · 2 Answers. Sorted by: 5. It's how memcpy works: it takes a pointer to data it will copy. Your data is pointer to float, so you need to pass pointer to pointer to float: #include int main () { float f = 20.0f; float* pf = &f; char data [sizeof (pf)]; memcpy (data, &pf, sizeof (data)); } Share. cute diy bed rails for toddler girl