realloc

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: The realloc reference says: The function may move the memory block to a new location, in which case the new location is returned. Does it mean that if I do this: void foo() { void* ptr = malloc( 1024 ); unsigned char* cptr = ( unsigned char* )ptr+256; ptr = realloc( ptr, 4096 ); } then cptr may become invalid if realloc moves the block? If yes, then does realloc signal in any way, that it will move the block, so that I can do something to prevent cptr from becoming invalid? 回答1: Yes, cptr will become invalid as realloc moves the block! And

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I am doing an exercise for fun from K and R C programming book. The program is for finding the longest line from a set of lines entered by the user and then prints it. Inputs: This is a test This is another long test this is another long testthis is another long test Observation: It runs fine for the first two inputs but fails for the larger string (3rd input) Errors: Error in `./longest': realloc(): invalid next size: 0x000000000246e010 *** Error in `./longest': malloc(): memory corruption (fast): 0x000000000246e030 *** My efforts: I have

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Disclaimer: This is homework. I am attempting it and do not expect or want anyone to do it for me. Just a few pointers (hehe) where I'm going wrong would be appreciated. The homework requires me to create an int* array that holds 10 elements, and then attempt to insert a million ints into it. Each insertion checks if the array needs to be resized, and if it does, I increase it's size so it can hold one more element. When I insert 10,000 elements, it works fine, but if I try 100,000 elements, I get the following error: *** glibc detected ***

堆和栈的区别： 栈的特征 执行的速度相对较快； 空间较小； 生存期由系统决定； 作用域较小； 有名空间，可以通过变量名或者数据名访问； 堆的特征 执行的速度相对较慢； 空间较大； 生存期由“自己”决定，malloc申请，free释放； 作用域很大（整个程序都可以访问）； 无名空间，只能通过指针使用； C语言空间的申请 malloc 功能： 分配 size 字节的未初始化内存。若分配成功，则返回指向分配内存块最低位（首位）字节的，为任何拥有基础对齐的对象类型对齐的指针。 头文件： #include<stdlib.h> 原型： void* malloc( size_t size ); 参数： size - 要分配的字节数 返回值： 成功时：返回指向新分配内存的指针。为避免内存泄漏，必须用 free() 或 realloc() 解分配返回的指针。 失败时：返回空指针。 说明： malloc申请的空间为连续空间；malloc申请的是没有初始化的空间； 返回值类型是void * 该类型表明malloc返回的地址空间中的数据类型是不确定，必须经过强制类型转换才可以使用。 realloc 功能： 先判断当前的指针是否有足够的连续空间，如果有，扩大mem_address指向的地址，并且将mem_address返回，如果空间不够，先按照newsize指定的大小分配空间

9.10. Symbol Resolution We know that run time linking occurs, but what if there is more than one symbol with the same name? How does the order of dependencies affect which will be chosen at run time? To better understand this, we need a multi-layer dependency tree of shared libraries such as the one in Figure 9.5 . 我们知道会发生运行时链接，但是如果有多个具有相同名称的符号会怎么样？ 依赖关系的顺序如何影响在运行时选择哪个？ 为了更好地理解这一点，我们需要一个共享库的多层依赖树，如图9.5所示。 Figure 9.5. Symbol Resolution with Shared Libraries. The executable resm comes from a source file called resm.C. It was linked with two shared libraries, libres.so (res.C) and libres2.so

I wrote a small piece of code like this: template <class T> void test() { T* ptr = nullptr; ptr = (T*)malloc(1 * sizeof(T)); new ((void*)ptr) T(T()); ptr = (T*)realloc(ptr, 2 * sizeof(T)); new ((void*)(ptr + 1)) T(T()); (ptr)->~T(); (ptr + 1)->~T(); free(ptr); } struct foo { foo() : ptr(malloc(10)) {} ~foo() { free(ptr); } void* ptr; }; int main() { test<int>(); // this is ok test<foo>(); // this is ok test<std::string>(); // memory error :( return 0; }; When T is [int] or [foo], everything works fine. But using [std::string] as T causes valgrind to report memory errors like this: ==18184==

My C program is crashing and I am too new to figure it out. It's very simple so far and I imagine the code is enough to figure out what is going wrong. I am simply trying to read a file line by line. I will double the memory of a structure once I am out of memory. If this is not enough information, I will give whatever else you need. Thank you very much for any help, as I have been stuck for hours now. /* John Maynard 1000916794 7/15/2013 HW-06 */ #include <stdio.h> #include <stdlib.h> #include <string.h> #define N 100 struct course { char subject[11]; int catalogNum; int sectionNum; int

Possible Duplicate: realloc and malloc functions #include<stdio.h> #include<stdlib.h> void main() { int *p; p = malloc(6); p = realloc(p, 10); if (p == NULL) { printf("error"); // when does p point to null consider i have enough space in prgrm //memory area but not in memory where realloc is trying to search //for the memory, I dont know how to explain that try to undrstnd exit(1); } } Take this example for the code, suppose the total memory is 10 bytes and 2 bytes is used by the declaration of pointer to type int and ohter 6 bytes by malloc function the remaining 2 bytes is occupied by other