将文本文件的大小放入缓冲区时出错

Question

if (fwarrior != NULL) {
/* Go to the end of the file. */

 if (fseek(fwarrior, 0, SEEK_END) == 0) {
 /* Get the size of the file. */
 long bufsize = ftell(fwarrior);
 if (bufsize == -1) 
 {
     printf("Error in reading the size of file"); 
 }

 /* Allocate our buffer to that size. */
 buffer = malloc(sizeof(char) * (bufsize + 1));

 /* Go back to the start of the file. */
 if (fseek(fwarrior, 0, SEEK_SET) == 0) 
 { 
     printf("Error = File is considered NULL"); 
 }

 /* Read the entire file into memory. */
 size_t newLen = fread(buffer, sizeof(char), bufsize, fwarrior);

 if (newLen == 0) 
 {
      fputs("Error reading file", stderr);
 } 

 else 
 {
      buffer[newLen] = '\0'; /* Just to be safe. */
 }

 }  
 }

在Windows上通过VS2012运行此代码时，出现的是"Error = File is considered NULL"

我试图将某个文件的内容分配到缓冲区中，并在以后使用sscanf创建一个单链表，以将文件的内容分配到它们各自的变量中。

我刚从一个网站上获得了上面的代码，该代码的制造商表示，上面的代码基本上是读取文件的全部内容，然后将它们分配到缓冲区中，以便以后可以使用sscanf 。

样品：

#include <stdio.h>
#include <stdlib.h>
typedef struct hero_data{
    char name[254];
    char title[254];
    int encoding;
    int startstr;
    double incstr;
    int startdex;
    double incdex;
    int startintel;
    double incintel;
    int basemindmg,basemaxdmg;
    double bat;
    double basearmor;
    struct hero_data *next;
    struct hero_data *type;
    struct hero_data *Class;
}hero;
int main()
{
hero *curr[] = {0};
hero *head;
hero *tail;
int totalwarrior = 0;
FILE *fwarrior;
char filename[256];
char *buffer = NULL;
size_t newLen;
printf("Name of Roster File for Warriors?(without .extension): \n");
scanf("%s",&filename);
strcat(filename,".txt");
fwarrior = fopen(filename,"r");

if (fwarrior != NULL) {
    /* Go to the end of the file. */
    if (fseek(fwarrior, 0, SEEK_END) == 0) {
        /* Get the size of the file. */
        long bufsize = ftell(fwarrior);
        if (bufsize == -1) 
        {
            printf("Error in reading the size of file"); 

        }

    /* Allocate our buffer to that size. */
    buffer = malloc(sizeof(char) * (bufsize + 1));

    /* Go back to the start of the file. */
    if (fseek(fwarrior, 0, SEEK_SET) == 0) //So is this the right way to use fseek?
    { 

    /* Read the entire file into memory. */
    size_t newLen = fread(buffer, sizeof(char), bufsize, fwarrior);

    if (newLen == 0) 
    {
        fputs("Error reading file", stderr);
    } 
    else 
    {
        buffer[newLen] = '\0'; /* Just to be safe. */
    }
}
}   

while(fgets(buffer, sizeof buffer, fwarrior) != NULL)
{
if(13 == sscanf(buffer,"%s[^,] , %s[^,] , %d , %d , %lf , %d , %lf , %d , %lf , %d , %d , %lf , %lf", &curr[totalwarrior]->name,&curr[totalwarrior]->title,&curr[totalwarrior]->encoding,&curr[totalwarrior]->startstr,&curr[totalwarrior]->incstr,&curr[totalwarrior]->startdex,&curr[totalwarrior]->incdex,&curr[totalwarrior]->startintel,&curr[totalwarrior]->incintel,&curr[totalwarrior]->basemindmg,&curr[totalwarrior]->basemaxdmg,&curr[totalwarrior]->bat,&curr[totalwarrior]->basearmor))
{
    if (head == NULL)
    {
        head = curr[totalwarrior];      
    }
    else 
    {
        tail->next=curr[totalwarrior];
    }
    tail = curr[totalwarrior];

    if (head!=NULL)
    {
        curr[totalwarrior] = head;
        do {
        printf("%s\n%s\n%d\n%d\n%.1lf\n%d\n%.1lf\n%d\n%.1lf\n%d\n%d\n%.1lf\n%.1lf\n\n",curr[totalwarrior]->name,curr[totalwarrior]->title,curr[totalwarrior]->encoding,curr[totalwarrior]->startstr,curr[totalwarrior]->incstr,curr[totalwarrior]->startdex,curr[totalwarrior]->incdex,curr[totalwarrior]->startintel,curr[totalwarrior]->incintel,curr[totalwarrior]->basemindmg,curr[totalwarrior]->basemaxdmg,curr[totalwarrior]->bat,curr[totalwarrior]->basearmor);
        curr[totalwarrior] = curr[totalwarrior]->next = curr[totalwarrior+1];
        curr[totalwarrior] = NULL; 
        printf("Before Total %d\n",totalwarrior);
        totalwarrior++;
        printf("Now Total %d\n",totalwarrior);
        }while(curr[totalwarrior-1] != NULL);
    } free(curr[totalwarrior]);
}
}
}
}
//I created a typedef struct named curr that is in the form of array. It is legit.
//I do not know the limit of the file so that's why I am trying to use the function above to get the size of the file in order to use `sscanf`.

//I made the code `13 == sscanf(...)` because within the file, there will be multiple "sets" of data that are in the set of 13 variables. Everytime when the program reads the 13th variable, I will add counter to `[totalwarrior]` of the typedef struct named `curr`.

这是程序将读取的示例文件：

Relay Chestdrop
Snow Damsel
230
16
1.7
16
1.6
21
2.9
38
44
1.7
1.24
Linnea Reversa
Vanquisher
214
18
1.5
16
1.5
27
3.2
40
58
1.7
1.24
Kyle
Hoarder
255
19
1.7
20
1.9
22
2.5
35
41
1.7
1.8
Leo
Wiccan Monster
236
16
1.7
15
1.5
22
3
42
48
1.7
1.1
Changer
Changer
191
19
2
24
3
17
1.5
37
46
1.6
1.36
Consortio Piercoptic
Elvish Sharpshooter
177
16
1.7
21
2.9
15
2.6
36
42
1.7
1.94
Tinklez
Osteoarcher
149
15
1.6
22
3
16
1.55
37
43
1.7
2.08
Weeeeheeee-urrr
Silhouette Devil
180
15
2
20
2.9
18
2
35
41
1.7
1.8
Deckard Haemofoot
Bovine Captain
71
24
2.3
14
1.5
23
1.6
47
57
1.7
2.96
Shelgar
Blessed Hero
92
21
2.4
20
2.4
18
1.5
42
51
1.6
1.8
Tomahawk
Genghis Tycoon
120
25
2.5
20
2.2
18
1.6
49
53
1.7
1.8
Beelzebub
Ruinbearer
108
26
3.2
11
0.9
13
2.1
53
69
1.7
0.54

Answer 1

fseek运行正常，但是您误解了结果。

返回值

如果成功，函数将返回零。 否则，它将返回非零值。 如果发生读取或写入错误，则会设置错误指示器（错误）。

（来自CPP参考 ）