c - 重新分配无效的下一个大小

Question

或者，重复 Facing an error — glibc detected free invalid next size (fast) .

我一直在努力解决这个问题，我尝试使用 valgrind 来追踪它，但似乎无法确定错误的确切来源。我可以调用该函数 4 次，但之后它会抛出 realloc invalid next size 错误。

确切的错误:* glibc检测到* ./matrix: realloc(): 下一个大小无效:0x0000000001a46010 ***

代码如下:

char line[101];
int nMatrix = -1;
Dims *dimensions;
List *vals = NULL;
int **values;
int **columns;
int **rowPointer;
int *lineCount;
int *highestRow;

void newMatrix()
{
    nMatrix++;
    values = realloc(values, sizeof(int*));
    columns = realloc(columns, sizeof(int*));
    rowPointer = realloc(rowPointer, sizeof(int*));
    dimensions = realloc(dimensions, sizeof(Dims));
    lineCount = realloc(lineCount, sizeof(int));
    highestRow = realloc(highestRow, sizeof(int));
}

void readIn(char* inputFile, int transpose)
{
    FILE *fr;
    int a = 0;
    int b = 0;
    int c = 0;
    newMatrix();
    if((fr = fopen(inputFile, "r")) != NULL)
    {
        while(fgets(line, 100, fr) != NULL)
        {
            if(lineCount[nMatrix] == 0)
            {
                if(transpose)
                    sscanf(line, "%d,%d", &dimensions[nMatrix].n, &dimensions[nMatrix].m);
                else
                    sscanf(line, "%d,%d", &dimensions[nMatrix].m, &dimensions[nMatrix].n);
                printf("nMatrix = %d, n%d,m%d\n", nMatrix, dimensions[nMatrix].n, dimensions[nMatrix].m);
            }
            else
            {
                sscanf(line, "%d,%d,%d", &a,&b,&c);
                //printf("a = %d, b = %d, c = %d\n", a,b,c);
                //rows[a] = insertList(c,b,rows[a]);c
                if(transpose)
                    vals = insertList(c, a, b, dimensions[nMatrix].m, dimensions[nMatrix].n, vals);
                else
                    vals = insertList(c, b, a, dimensions[nMatrix].m, dimensions[nMatrix].n, vals);
            }
            lineCount[nMatrix]++;
        }
        values[nMatrix] = calloc(lineCount[nMatrix], sizeof(int));
        columns[nMatrix] = calloc(lineCount[nMatrix], sizeof(int));
        rowPointer[nMatrix] = calloc(((dimensions[nMatrix].m)+1), sizeof(int));
        values[nMatrix][lineCount[nMatrix]] = 0;
        columns[nMatrix][lineCount[nMatrix]] = 0;
        int i = 0;
        int lastRow = -1;
        while(i < dimensions[nMatrix].m)
        {
            rowPointer[nMatrix][i] = -1;
            i++;
        }
        i = 0;
        List *temp = NULL;
        while(vals != NULL)
        {
            temp = vals;
            //printf("pos = %d, row = %d, col = %d, val = %d, i=%d", temp->position, temp->row, temp->column, temp->value, i);
            if(lastRow != temp->row)
            {
                rowPointer[nMatrix][temp->row] = i;
                lastRow = temp->row;
                highestRow[nMatrix] = i;
            }
            values[nMatrix][i] = temp->value;
            columns[nMatrix][i] = temp->column;
            i++;
            vals = temp->next;
            free(temp);

        }
        rowPointer[nMatrix][dimensions[nMatrix].m] = lineCount[nMatrix]-1;
        fclose(fr);
        return;
    }
    fclose(fr);
    printf("File not found\n");
    return;
}

Answer 1

对于您“分配”的每个新矩阵，您应该扩展您的全局指针列表。你不知道。您只需将它们重新分配为与之前相同的大小即可:

这个:

void newMatrix()
{
    nMatrix++;
    values = realloc(values, sizeof(int*));
    columns = realloc(columns, sizeof(int*));
    rowPointer = realloc(rowPointer, sizeof(int*));
    dimensions = realloc(dimensions, sizeof(Dims));
    lineCount = realloc(lineCount, sizeof(int));
    highestRow = realloc(highestRow, sizeof(int));
}

应该是这样的:

void newMatrix()
{
    nMatrix++;
    values = realloc(values, (nMatrix+1)*sizeof(int*));
    columns = realloc(columns, (nMatrix+1)*sizeof(int*));
    rowPointer = realloc(rowPointer, (nMatrix+1)*sizeof(int*));
    dimensions = realloc(dimensions, (nMatrix+1)*sizeof(Dims));
    lineCount = realloc(lineCount, (nMatrix+1)*sizeof(int));
    highestRow = realloc(highestRow, (nMatrix+1)*sizeof(int));
}

注意:使用 (nMatrix+1) 值是因为您以 nMatrix 作为 (-1) 开始，并且在第一次递增时它是 (0)，下一个是 (1)，依此类推...即它总是对插入的最后一行进行索引，但由于希望显而易见的原因，您的 vector 幅度需要+1。

我强烈建议您考虑当 realloc() 失败时会发生什么，因为它将返回 NULL，并且在进程中泄漏 所指向的任何内存。您传入的指针。

可能还有其他问题，但这是我首先想到的问题。