[英]Invalid Write Size of 8 Valgrind
我正在编写一个解析.csv文件的函数,但是valgrind出现错误。 具体来说就是:
==5450== Invalid write of size 8
==5450== at 0x404FA0: parse_exemplars (util.c:568)
==5450== by 0x40508E: get_test_and_train_data (util.c:595)
==5450== by 0x402737: setup (pony_gp.c:727)
==5450== by 0x4027E5: main (pony_gp.c:761)
这是带有指示错误行的代码:
csv_reader *reader = init_csv(file_name, ',');
double **fitness_cases, *targets;
int num_columns = 122;
int num_lines = 121;
// leave space for NULL at end
fitness_cases = malloc(sizeof(double **) * num_lines);
for (int i = 0; i < num_lines; i++) {
fitness_cases[i] = malloc(sizeof(double *));
for (int k = 0; k < num_columns; k++) {
fitness_cases[i] = malloc(sizeof(double) * (num_columns - 1));
}
}
// leave space for NAN at end
targets = malloc(sizeof(double) * (num_lines));
csv_line *row;
int f_i = 0;
int t_i = 0;
while ((row = readline(reader))) {
int i;
for (i = 0; i < num_columns; i++) {
if (i == num_columns - 1) {
targets[t_i++] = atof(row->content[i]);
}
else {
fitness_cases[f_i][i] = atof(row->content[i]);
}
}
fitness_cases[f_i][i-1] = (double)NAN; //<----- This is where it says the error is, line 568.
f_i++;
}
每当我检查Fitness_cases [f_i] [i-1]的大小时,我总是得到与(double)NAN大小相同的值,所以我猜想它早于该函数了吗?
到github页面的链接是(我正在询问的此函数当前未在仓库中更新): https : //github.com/dyingpie1/pony_gp_c
fitness_cases[f_i][i-1] = (double)NAN;
i-1的值在此处为num_columns -1
但由于您已将空间分配为
fitness_cases[i] = malloc(sizeof(double) * (num_columns - 1));
第二个数组下标的最大索引可以少一个,即num_columns-2,否则您将超出范围
例如
fitness_cases[i] = 3 * sizeof(double);
fitness_cases[i][0]
, fitness_cases[i][1]
, fitness_cases[i][2]
有效, fitness_cases[i][3]
超出范围,将导致无效写入,如valgrind所示。
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