Question

请帮帮我。当我运行这个程序时，我无法弄清楚为什么我会得到一个核心转储。在返回任何内容之前，我可以打印all_albums_p就好了。为什么我会收到core dumped？

#include "music_server.h"

struct album_ {
  int num_tracks;
  char **tracks;
  int **playlist_hits;

};
typedef struct album_ album;

album *parse_album(FILE *album_file,int *number_of_albums){

  int number_of_album,number_of_tracks,number_of_charaters;
  int i,j;
  char dummy_space;
  int *p;

  fscanf(album_file,"%d", &number_of_album);

  *number_of_albums = number_of_album;

  album *all_albums_p = (album *)malloc(sizeof(album)*number_of_album);

  for(j=0;j<number_of_album;j++){

    fscanf(album_file,"%d", &all_albums_p[j].num_tracks);

    all_albums_p[j].tracks = calloc(all_albums_p[j].num_tracks,sizeof(char));
    all_albums_p[j].playlist_hits = calloc(all_albums_p[j].num_tracks,sizeof(int));

    /*Line 27*/ for(i=0;i<all_albums_p[j].num_tracks;i++){

      fscanf(album_file,"%d", &number_of_charaters);

      all_albums_p[j].tracks[i] = (char *)calloc(number_of_charaters+1,sizeof(char));
      all_albums_p[j].playlist_hits[i] = (int *)malloc(sizeof(int));
      all_albums_p[j].playlist_hits[i] = 0;
      fscanf(album_file," ",dummy_space);
      fscanf(album_file, "%[^\n]s", all_albums_p[j].tracks[i]);
    }
  }
  return all_albums_p;
}

main(int argc, char *argv[]){

  int i,j;
  int *number_of_albums,*number_of_tracks,a;
  a=0;
  number_of_albums = &a;

  album *all_tracks_ptr;

  album_file = fopen(argv[1],"r");
  transaction_file = fopen(argv[2],"r");

  if((album_file == NULL) || (transaction_file == NULL)){
    printf("Either %s or %s could not be open");
  }else{

    all_tracks_ptr = parse_album(album_file,number_of_albums);


    int number_of_tracks[*number_of_albums];
  }
}

错误：

Bus Error (core dumped)

(gdb) bt
#0  0xff277c9c in _smalloc () from /lib/libc.so.1
#1  0xff277d10 in malloc () from /lib/libc.so.1
#2  0xff263830 in calloc () from /lib/libc.so.1
#3  0x00010dd8 in parse_album (album_file=0xff3675bc,
    number_of_albums=0xffbff894) at functions.c:27
#4  0x00010b80 in main (argc=3, argv=0xffbff90c) at project3.c:19

Answer 1

您应该在下面分配sizeof(char*)而不是sizeof(char)

all_albums_p[j].tracks = alloc(all_albums_p[j].num_tracks,sizeof(char*));

Answer 2

因为它看起来像一条Unix消息（“Bus Error（core dumped）”），我假设你正在使用某种类型的Unix。

因此，在打开调试信息输出并关闭优化的情况下编译程序。如果您使用的是gcc或gcc兼容的内容，则可能是-g -O0命令行选项。

然后运行你的程序并让它崩溃。找到核心转储（在本例中我将其称为corefile），然后键入：

gdb programname corefile

然后，当您收到gdb提示时，键入bt（对于backtrace）以查看程序的堆栈帧。这将告诉你程序崩溃的位置，你可以更仔细地检查程序的那一部分。

<强>更新

我认为你的问题在这里：

all_albums_p[j].tracks = calloc(all_albums_p[j].num_tracks,sizeof(char));

album.tracks定义为char**。但是，您分配给all_albums_p[j].tracks的内容是num_tracks char大小的内存块。您需要为其分配一块足以容纳num_tracks char *的内存块。所以你可能需要将行改为：

all_albums_p[j].tracks = (char **) calloc(all_albums_p[j].num_tracks,sizeof(char *));

Answer 3

使用调试器或valgrind并找出问题所在的行。然后你会知道代码的哪一部分是坏的。

为什么我会把核心倾倒？

3 个答案: