最近在一块新的板子下作开发， 有些变量发生异常（就是我们不想到的值），可以加上backtrace，知道是哪个函数调用它，导致出现异常， 就像死机了，你可以gdb和core文件用bt 命令，查看死机在哪里（有一种 情况 不能看见， 就是发生信号异常不在本文范围 ）， 本人感觉还有用， 关说不炼、假把式，下面是实现代码：

首先实现核心代码backtrace函数：

extern void * __libc_stack_end;# define BOUNDED_N(PTR, N) (PTR)
#define BOUNDED_1(PTR) BOUNDED_N (PTR, 1)
/* Get some notion of the current stack.  Need not be exactly the topof the stack, just something somewhere in the current frame.  */
#ifndef CURRENT_STACK_FRAME
# define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
#endif/* By default we assume that the stack grows downward.  */
#ifndef INNER_THAN
# define INNER_THAN <
#endif/* By default assume the `next' pointer in struct layout points to thenext struct layout.  */
#ifndef ADVANCE_STACK_FRAME
# define ADVANCE_STACK_FRAME(next) BOUNDED_1 ((struct layout *) (((int)next) - 4))
#endif/* By default, the frame pointer is just what we get from gcc.  */
#ifndef FIRST_FRAME_POINTER
# define FIRST_FRAME_POINTER  (__builtin_frame_address (0) - 4)
#endifint backtrace (void **array, int size)
{struct layout *current;void *top_frame;void *top_stack;int cnt = 0;top_frame = FIRST_FRAME_POINTER;top_stack = CURRENT_STACK_FRAME;/* We skip the call to this function, it makes no sense to record it.  */current = BOUNDED_1 ((struct layout *) top_frame);while (cnt < size){if ((void *) current->fp INNER_THAN top_stack|| !((void *) current->fp INNER_THAN __libc_stack_end)){/* This means the address is out of range.  Note that for thetoplevel we see a frame pointer with value NULL which clearly isout of range.  */break;}array[cnt] = current->lr;cnt++;current = ADVANCE_STACK_FRAME (current->fp);}/** In leaf function* gcc not push lr when call it*/printf(" ");return cnt;
}

下面就是将她加入一个文件中了

/*** @fn          writeToFile* @brief       backtrace写入文件* @param[in]   *pIndex: 目录*              *pAppend: 附加信息* @param[out]* @return      BSTAR_OK    BSTAR_FAIL*/
int writeToFile(const char *pIndex, const char* pAppend)
{int j, nptrs = 0;void *buffer[100];char str[1024] = {0};int fd = 0;if(NULL == pIndex){fprintf(stderr, "the Index is NULL!\n");return -1;}if((fd = open(pIndex, O_RDWR|O_APPEND, 0644)) < 0){fd = open(pIndex, O_RDWR|O_CREAT|O_APPEND, 0644);}nptrs = backtrace(buffer, 100);if(NULL != pAppend){write(fd, pAppend, strlen(pAppend));memset(str, 0, 1024);}for (j = 0; j < nptrs; j++){sprintf(str, "%p\n", buffer[j]);write(fd, str, strlen(str));memset(str, 0, 1024);}write(fd, "================\n", strlen("================\n"));close(fd);return 0;
}

好了，就是这些了， 你可以将她编写成so库， 那样就方便调用了