free

Double free or corruption error with Stack and Binary Expression Tree

由 十年热恋 提交于 2019-12-08 06:26:32
问题 I am getting the following error when trying to build a binary expression tree from a Stack. I believe the issue is where I am popping in the recursive function, I think I am popping on an empty stack but I don't know the solution. * glibc detected ./interp: double free or corruption (fasttop): 0x0934d018 ** Here is my code: //This is the main int main(int argc, char *argv[]){ TreeNode *node; StackNode *stack = NULL; push(&stack, "a"); push(&stack, "b"); push(&stack, "+"); //while (emptyStack

Function interposition only working for malloc not free

由 橙三吉。 提交于 2019-12-07 23:29:34
问题 I've come across a small problem while monitoring malloc and free trough the use of function interposition. When performing the function interposition for just malloc, it works as exepcted. However, when trying to interpose free as well it ends up in a loop; i seems like free is recursivly invoked but i just dont know why. This is the code for the malloc and free functions. (mod_malloc_free.c) #define _GNU_SOURCE #include <stdio.h> #include <stdint.h> #include <dlfcn.h> void* malloc(size_t

free a pointer to dynamic array in c

由 假装没事ソ 提交于 2019-12-07 08:37:18
问题 I create a dynamic array in c with malloc. e.g.: myCharArray = (char *) malloc(16); now if I make a function like this and pass myCharArray to it: reset(char * myCharArrayp) { free(myCharArrayp); } will that work, or will I somehow only free the copy of the pointer (myCharArrayp) and not the actual myCharArray? 回答1: That will be fine and free the memory as you expect. I'd consider writing a function like void reset(char** myPointer) { if (myPointer) { free(*myPointer); *myPointer = NULL; } }

Freeing memory returned from C functions

由 可紊 提交于 2019-12-07 06:11:31
问题 In C, which is the better practice when it comes to freeing memory returned from functions: Provide a "destructor" function that encapsulates the call to free(). Require users to free() the returned pointer themselves. For example, to open and close a file we do: FILE* f = fopen("blah", "w"); fclose(f); Is this preferable to: FILE* f = fopen("blah", "w"); fclose(f); free(f); Warning: Don't call free() on a FILE pointer. I only use it a hypothetical implementation here. And what about cases

How to handle free() errors in C?

由 旧街凉风 提交于 2019-12-07 05:02:46
问题 Suppose that I have used a free() function to free a memory that,for many reasons, I'm not allowed to. How can I stop my C application from crashing and just generate an error and continue the execution? I don't have try-catch kind of provision here (like C++/java...). Is there any way to ignore this error and continue execution? If yes, How do you do that? More importantly, is it advisable to do so (continuing execution considering this memory error occurred)? Thank you 回答1: There is nothing

c malloc questions (mem corruption)

由 限于喜欢 提交于 2019-12-06 14:21:43
问题 When using malloc, if it produces a core dump with the error: malloc(): memory corruption: ....... *** Does this mean that malloc tried to allocate memory that was not free to allocate? IF so what are the causes of this? 回答1: It completely depends on your malloc implementation, but usually what this is means is that at some point prior to that malloc something wrote more data to a malloced buffer than its size. A lot of malloc implementations store some of their data inline with their memory,

C Programming- Malloc/Free

由 不问归期 提交于 2019-12-06 11:13:47
So I have a code and when I run it, it hangs when I enter a size greater than 3. When it's exactly 3 it runs smoothly. I narrowed down the problem to malloc and free and I don't know what the problem is. I'm new at this so any help is appreciated. do //repeatedly ask the user to put a number between 3-9 { printf("Enter the size of the game board between 3-9: "); scanf("%d", &size); }while(size<3 || size>9); if((board = (char***)malloc(sizeof(char**)*size))==NULL) printf("Memory Allocation failed\n"); for(i=0; i<size; i++) { if((board[i] = (char**)malloc(sizeof(char*)*size))==NULL) printf(

Function interposition only working for malloc not free

由 為{幸葍}努か 提交于 2019-12-06 10:28:47
I've come across a small problem while monitoring malloc and free trough the use of function interposition. When performing the function interposition for just malloc, it works as exepcted. However, when trying to interpose free as well it ends up in a loop; i seems like free is recursivly invoked but i just dont know why. This is the code for the malloc and free functions. (mod_malloc_free.c) #define _GNU_SOURCE #include <stdio.h> #include <stdint.h> #include <dlfcn.h> void* malloc(size_t size) { static void* (*real_malloc)(size_t) = NULL; printf("%s\n", "inside shared malloc"); if(!real

Conflicting types for “free”

由 ☆樱花仙子☆ 提交于 2019-12-06 04:37:27
问题 I'm getting the error Conflicting types for 'free' on the call to free() function below. int main ( ) { char fx [] = "x^2+5*x-1"; node * fxNode = buildTree(fx, sizeof(fx)/sizeof(char)); printf(deriveFromTree(fxNode)); // Should print "2*x+5" free(fxNode); return 0; } Can't figure out why. Not sure if this matter, but what's above it is #include <stdio.h> char opstack [5] = {'+','-','*','^', '\0'}; unsigned short int lowerOpPrecedence ( char, char, char * ); int stringToUnsignedInt ( char *,

The differences between free in C and delete in C++?

由 与世无争的帅哥 提交于 2019-12-06 04:11:59
问题 I know the free operation in C is to tell the compiler this particular memory block is free for compiler to use for further allocation, but the memory is not released. What about the delete in C++? the same as free? 回答1: There are two notions of delete in C++: One is the operator , declared as ::operator delete(void*) , which basically only frees up the memory and isn't usually thought about by most programmers. The other is the delete expression , delete p; , where p is a T* . The expression
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