C 将文本文件大小放入缓冲区时出错

当在Windows上通过VS2012运行此代码时，显示的是“错误=文件被视为空”

我试图将某个文件的内容分配到缓冲区，然后使用

sscanf

创建一个单链表，将文件的内容分配到各自的变量中

我刚从一个网站上得到了上面的代码，这个代码的制作者说上面的代码基本上读取了文件的全部内容，然后将它们分配到缓冲区，以便我们以后可以使用

sscanf

样本：

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. */
 }

 }  
 }

---

fseek

运行正常，但您误解了结果

返回值

如果成功，函数将返回零。 否则，它将返回非零值。 如果发生读或写错误，则设置错误指示器（ferror）

---

（from）

发布一个最短的示例，演示我们可以实际编译的问题。发布与您的问题相关的部分：

buffer[++newLen]='\0'应该是：
缓冲区[newLen]='\0'顺便说一下。如果读取10个字节，则需要将
缓冲区[10]
设置为
\0
，而不是
缓冲区[11]
。如果您实际读取
bufsize
字节，那么您将写入超过缓冲区末尾的内容。这也不是“为了安全”——这是必要的（至少如果你在处理字符串），因为
fread（）
不会为你添加终止NUL。我已经包含了实际的代码。编译并运行时，它什么也不做
#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`.

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16
1.7
16
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21
2.9
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44
1.7
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214
18
1.5
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1.5
27
3.2
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58
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Kyle
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19
1.7
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2.5
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41
1.7
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Leo
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2
24
3
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Consortio Piercoptic
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1.7
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2.9
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2.6
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180
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2
20
2.9
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2
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71
24
2.3
14
1.5
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57
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Shelgar
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92
21
2.4
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2.4
18
1.5
42
51
1.6
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Tomahawk
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120
25
2.5
20
2.2
18
1.6
49
53
1.7
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108
26
3.2
11
0.9
13
2.1
53
69
1.7
0.54