如何解决ApplicationName.exe 已触发 Visual Studio 中的断点
typedef struct Tuple
{
int row;
int col;
int data;
} Tuple;
int** createMatrix(int r,int c)
{
int** mat = (int**)malloc(sizeof(int*) * r);
for (int i = 0; i < r; i++)
mat[i] = malloc(sizeof(int) * c);
return mat;
}
Tuple* createTuple(int** mat,int r,int c)
{
int count = 0;
for (int i = 0; i < r; i++)
for (int j = 0; j < c; j++)
if (mat[i][j])
count++;
Tuple* tuple = (Tuple*)malloc(sizeof(Tuple) * count);
tuple[0].col = c;
tuple[0].row = r;
tuple[0].data = count;
int k = 1;
for (int i = 0; i < r; i++)
for (int j = 0; j < c; j++)
if (mat[i][j])
{
tuple[k].col = j;
tuple[k].row = i;
tuple[k++].data = mat[i][j];
}
return tuple;
}
Tuple* fastTranspose(Tuple* tuple)
{
Tuple* trans = (Tuple*)calloc((tuple[0].data + 1),sizeof(Tuple) );
trans[0].col = tuple[0].row;
trans[0].row = tuple[0].col;
trans[0].data = tuple[0].data;
int* rowTerms = (int*)malloc(sizeof(int) * tuple[0].col);
int* startingPos = (int*)malloc(sizeof(int) * tuple[0].col);
for (int i = 0; i < tuple[0].col; i++)
rowTerms[i] = 0;
for (int i = 1; i <= tuple[0].data; i++)
rowTerms[tuple[i].col]++;
startingPos[0] = 1;
for (int i = 1; i < tuple[0].col; i++)
startingPos[i] = startingPos[i - 1] + rowTerms[i - 1];
for (int i = 1; i <= tuple[0].data; i++)
{
int j = startingPos[tuple[i].col]++;
trans[j].col = tuple[i].row;
trans[j].row = tuple[i].col;
trans[j].data = tuple[i].data;
}
free(rowTerms);
free(startingPos);
return trans;
}
void printTuple(Tuple* tuple)
{
printf("\nRow Col Val:\n");
for (int i = 0; i <= tuple[0].data; i++)
{
printf("%3d%4d%4d\n",tuple[i].row,tuple[i].col,tuple[i].data);
}
}
int main()
{
int** mat = createMatrix(3,4);
printf("Enter data:\n");
for (int i = 0; i < 3; i++)
for (int j = 0; j < 4; j++)
scanf("%d",&mat[i][j]);
Tuple* tuple = createTuple(mat,3,4);
printf("Original tuple:");
printTuple(tuple);
Tuple* trans = fastTranspose(tuple);
printf("Tuple transpose:");
printTuple(trans);
free(trans);
free(tuple);
for (int i = 0; i < 3; i++)
free(mat[i]);
free(mat);
}
为什么我没有在函数fastTranspose的第一行设置断点？
我查看了类似的问题，但找不到解决方案。它是一个求矩阵转置的程序。我们首先动态分配一个二维矩阵。然后将其转换为稀疏矩阵表示形式，该形式使用结构来存储行、列和数据的值。 我尝试打印矩阵和元组的值。有效。但是进入快速转置功能时突然触发断点。
我们通常会自己在visual studio中放置一个断点。为什么是IDE放的？
解决方法
Visual Studio 在那里放置了一个断点很有帮助，因为您在那个地方遇到了错误。如果我在最近的 Linux (Mint 20) 和最近的 clang (12.0.0) 上执行此操作，我会得到以下输出：
$ echo -e '1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12' | ./so_tmat
Enter data:
Original tuple:
Row Col Val:
3 4 12
0 0 1
0 1 2
0 2 3
0 3 4
1 0 5
1 1 6
1 2 7
1 3 8
2 0 9
2 1 10
2 2 11
2 3 12
tuple[0].data + 1 = 13,sizet(Tuple) = 12
so_tmat: malloc.c:2379: sysmalloc: Assertion `(old_top == initial_top (av) && old_size == 0) || ((unsigned long) (old_size) >= MINSIZE && prev_inuse (old_top) && ((unsigned long) old_end & (pagesize - 1)) == 0)' failed.
Aborted (core dumped)
GDB（GNU 调试器）的回溯指向与 VS 相同的行。
如果我（你的里程数可能会有所不同，因为：谷歌）将它原样复制并粘贴到谷歌中，我得到了 Why do I get a C malloc assertion failure? 作为第一个命中。接受的答案以正确的方式指出，我们将向 Valgrind 寻求一些提示。
$ echo -e '1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12' | valgrind --track-origins=yes --leak-check=full --show-leak-kinds=all ./so_tmat
==16047== Memcheck,a memory error detector
==16047== Copyright (C) 2002-2017,and GNU GPL'd,by Julian Seward et al.
==16047== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==16047== Command: ./so_tmat
==16047==
Enter data:
==16047== Invalid write of size 8
==16047== at 0x40144D: createTuple (so_tmat.c:38)
==16047== by 0x40144D: main (so_tmat.c:89)
==16047== Address 0x4a796a0 is 0 bytes after a block of size 144 alloc'd
==16047== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16047== by 0x401377: createTuple (so_tmat.c:28)
==16047== by 0x401377: main (so_tmat.c:89)
==16047==
==16047== Invalid write of size 4
==16047== at 0x401452: createTuple (so_tmat.c:39)
==16047== by 0x401452: main (so_tmat.c:89)
==16047== Address 0x4a796a8 is 8 bytes after a block of size 144 alloc'd
==16047== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16047== by 0x401377: createTuple (so_tmat.c:28)
==16047== by 0x401377: main (so_tmat.c:89)
==16047==
...
我们可以停在这里，因为我们找到了原因：您有缓冲区溢出，因为您在 count = 0 中以 createMatrix(int r,int c) 开头，这导致缺少最后一个 Tuple 所需的内存.将其更改为 count = 1，它应该可以工作。
让我们检查一下：
$ echo -e '1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12' | valgrind --track-origins=yes --leak-check=full --show-leak-kinds=all ./so_tmat
==16215== Memcheck,a memory error detector
==16215== Copyright (C) 2002-2017,by Julian Seward et al.
==16215== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==16215== Command: ./so_tmat
==16215==
Enter data:
Original tuple:
Row Col Val:
3 4 13
0 0 1
0 1 2
0 2 3
0 3 4
1 0 5
1 1 6
1 2 7
1 3 8
2 0 9
2 1 10
2 2 11
2 3 12
==16215== Invalid read of size 4
==16215== at 0x4014A0: printTuple (so_tmat.c:78)
==16215== by 0x4014A0: main (so_tmat.c:91)
==16215== Address 0x4a796b4 is 8 bytes after a block of size 156 alloc'd
==16215== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16215== by 0x40137A: createTuple (so_tmat.c:28)
==16215== by 0x40137A: main (so_tmat.c:89)
...
还有一个问题，现在是在printTuple(Tuple* tuple)中，因为我们改变了count的初始化，但是没有调整tuple[0].data中的值，所以for (int i = 0; i <= tuple[0].data; i++)行的上限{1}} 太大。在这里或那里更正它，并不重要，我会更正循环中的上限，因为 tuple[0].data 包含正确数量的非零条目。因此将循环更改为 for (int i = 0; i < tuple[0].data; i++)
再次检查：
$ echo -e '1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12' | valgrind --track-origins=yes --leak-check=full --show-leak-kinds=all ./so_tmat
==16328== Memcheck,a memory error detector
==16328== Copyright (C) 2002-2017,by Julian Seward et al.
==16328== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==16328== Command: ./so_tmat
==16328==
Enter data:
Original tuple:
Row Col Val:
3 4 13
0 0 1
0 1 2
0 2 3
0 3 4
1 0 5
1 1 6
1 2 7
1 3 8
2 0 9
2 1 10
2 2 11
2 3 12
tuple[0].data + 1 = 14,sizet(Tuple) = 12
==16328== Invalid read of size 4
==16328== at 0x4015B1: fastTranspose (so_tmat.c:56)
==16328== by 0x4015B1: main (so_tmat.c:92)
==16328== Address 0x4a796b0 is 4 bytes after a block of size 156 alloc'd
==16328== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16328== by 0x40137A: createTuple (so_tmat.c:28)
==16328== by 0x40137A: main (so_tmat.c:89)
==16328==
==16328== Invalid read of size 4
==16328== at 0x4017D0: fastTranspose (so_tmat.c:63)
==16328== by 0x4017D0: main (so_tmat.c:92)
==16328== Address 0x4a796b0 is 4 bytes after a block of size 156 alloc'd
==16328== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16328== by 0x40137A: createTuple (so_tmat.c:28)
==16328== by 0x40137A: main (so_tmat.c:89)
==16328==
==16328== Invalid read of size 4
==16328== at 0x4017DF: fastTranspose (so_tmat.c:64)
==16328== by 0x4017DF: main (so_tmat.c:92)
==16328== Address 0x4a796ac is 0 bytes after a block of size 156 alloc'd
==16328== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16328== by 0x40137A: createTuple (so_tmat.c:28)
==16328== by 0x40137A: main (so_tmat.c:89)
==16328==
==16328== Invalid read of size 4
==16328== at 0x4017ED: fastTranspose (so_tmat.c:66)
==16328== by 0x4017ED: main (so_tmat.c:92)
==16328== Address 0x4a796b4 is 8 bytes after a block of size 156 alloc'd
==16328== at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==16328== by 0x40137A: createTuple (so_tmat.c:28)
==16328== by 0x40137A: main (so_tmat.c:89)
...
查看有问题的行（您的行号可能不同）：与之前相同的上限问题。更改并再次检查。
$ echo -e '1\n2\n3\n4\n5\n6\n7\n8\n9\n10\n11\n12' | valgrind --track-origins=yes --leak-check=full --show-leak-kinds=all ./so_tmat
==16420== Memcheck,a memory error detector
==16420== Copyright (C) 2002-2017,by Julian Seward et al.
==16420== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==16420== Command: ./so_tmat
==16420==
Enter data:
Original tuple:
Row Col Val:
3 4 13
0 0 1
0 1 2
0 2 3
0 3 4
1 0 5
1 1 6
1 2 7
1 3 8
2 0 9
2 1 10
2 2 11
2 3 12
tuple[0].data + 1 = 14,sizet(Tuple) = 12
Tuple transpose:
Row Col Val:
4 3 13
0 0 1
0 1 5
0 2 9
1 0 2
1 1 6
1 2 10
2 0 3
2 1 7
2 2 11
3 0 4
3 1 8
3 2 12
==16420==
==16420== HEAP SUMMARY:
==16420== in use at exit: 0 bytes in 0 blocks
==16420== total heap usage: 10 allocs,10 frees,5,548 bytes allocated
==16420==
==16420== All heap blocks were freed -- no leaks are possible
==16420==
==16420== For lists of detected and suppressed errors,rerun with: -s
==16420== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
很好，没有问题了。至少对于那个确切的输入。但是我在 printf("tuple[0].data + 1 = %d,sizet(Tuple) = %zu\n",tuple[0].data + 1,sizeof(Tuple) ); 之前挤了一点 calloc()，它说
tuple[0].data + 1 = 14,sizet(Tuple) = 12
那太多了Tuple；节省一些内存并通过删除 + 1 中的 calloc 来更改它。就是这样。
我在这里使用了 Unix 工具，其中大部分都可用于 Windows，但 VS 也有所有必要的工具，它们只是名称不同，使用方式不同。尝试找到它们并与它们一起检查您的原始代码（您现在知道其中的错误）以熟悉该工具链。您真的需要这些知识！
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