问题描述
为什么下面的工作不会引发某种细分错误?
Why does the following work and not throw some kind of segmentation fault?
char *path = "/usr/bin/";
char *random = "012";
// path + random + \0
// so its malloc(13), but I get 16 bytes due to memory alignment (im on 32bit)
newPath = (char *) malloc(strlen(path) + strlen(random) + 1);
strcat(newPath, path);
strcat(newPath, "random");
// newPath is now: "/usr/bin/012\0" which makes 13 characters.
但是，如果我添加
strcat(newPath, "RANDOMBUNNIES");
该调用是否应该失败，因为strcat使用的内存多于分配的内存?因此，不应该
shouldn't this call fail, because strcat uses more memory than allocated? Consequently, shouldn't
free(newPath)
也会失败，因为它尝试释放16个字节，但我使用了26个字节("/usr/bin/012RANDOMBUNNIES \ 0")?
also fail because it tries to free 16 bytes but I used 26 bytes ("/usr/bin/012RANDOMBUNNIES\0")?
非常感谢！
推荐答案
大多数情况下，这种溢出问题不会使您的程序在浓烟和硫磺味中爆炸.更为微妙的是:在超出运行变量之后分配的变量将被更改，从而在以后导致程序无法解释且看似随机的行为.
Most often this kind of overrun problems doesn't make your program explode in a cloud of smoke and the smell of burnt sulphur. It's more subtle: the variable that is allocated after the overrun variable will be altered, causing unexplainable and seemingly random behavior of the program later on.
这篇关于写的字符多于分配的字符.为什么不失败?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！