用stat函数无法获取文件大小

各位，我打算用stat里面的st-size 函数获取文件的大小，但是怎么调试得到的值就是0.

 int
main (void)
{
    char *fileName = "abcd.txt";

    SM_FileHandle fh;

    createPageFile(fileName);

    openPageFile (fileName, &fh);
    int a = fh.totalNumPages;
    printf("%d+%s", a, "main");

    return 0;
}

 RC createPageFile (char *fileName){
    FILE *pageFile;
    pageFile = fopen(fileName,"w");   //Creates an empty file for both reading and writing.
//    for(int i = 0; i < PAGE_SIZE; i++){      //Creates one page in the file. The size of page is 4096 bytes
//        fwrite("\0", 1, 1, pageFile);
//    }

     fwrite("abc", 3, 1, pageFile);


    struct stat fileStat;
    stat(fileName, &fileStat);
    int fileSize = fileStat.st_size;   //Get the size of file.

    printf("%d+%s\n", fileSize, "create file");

    return RC_OK;
}

 RC openPageFile (char *fileName, SM_FileHandle *fHandle){
    FILE *pageFile;
    pageFile = fopen(fileName,"r");  //Opens the file.

    if(pageFile == NULL){            //If cannot found the file, return "RC_FILE_NOT_FOUND".
        return RC_FILE_NOT_FOUND;
    }else{
        struct stat fileStat;
        stat(fileName, &fileStat);
        int fileSize = fileStat.st_size;   //Get the size of file.

        fHandle->fileName = fileName;
        fHandle->totalNumPages = fileSize/PAGE_SIZE;
        fHandle->curPagePos = 0;
        fHandle->mgmtInfo = pageFile;

        printf("%d+%s\n", fileSize, "open file");

        return RC_OK;
    }
}

RC openPageFile (char *fileName, SM_FileHandle *fHandle){
FILE *pageFile;
pageFile = fopen(fileName,"r"); //Opens the file.

if(pageFile == NULL){            //If cannot found the file, return "RC_FILE_NOT_FOUND".
    return RC_FILE_NOT_FOUND;
}else{
    struct stat fileStat;
    stat(fileName, &fileStat);
    int fileSize = fileStat.st_size;   //Get the size of file.

    fHandle->fileName = fileName;
    fHandle->totalNumPages = fileSize/PAGE_SIZE;
    fHandle->curPagePos = 0;
    fHandle->mgmtInfo = pageFile;

    printf("%d+%s\n", fileSize, "open file");

    return RC_OK;
}

}

你需要在用fopen创建文件后，调用fclose，因为在向文件写数据时，实际是将数据输到缓冲区，待缓冲区充满后才正式输出给文件，如果当数据未充满缓冲区而程序结束运行，就会将缓冲区中的数据丢失。用fclose函数关闭文件，他先将缓冲区中的数据输出到磁盘文件然后才释放文件指针变量，从而避免了数据丢失。而stat是用来获取文件的实际状态的，没用fclose的话，实际数据没有保存到文件中，获取的st_size就是0了。

#include
#include
#include
static unsigned long getFileSize(const char *filePath)
{//EFile类获取文件大小
unsigned long filesize = -1;
struct stat statbuff;
if(stat(filePath, &statbuff) < 0)
return filesize;
else
filesize = statbuff.st_size;
printf("func %s, LINE %d----------filesize = %lu, filePath = %s,\n", func, LINE, filesize, filePath);
return filesize;
}

测试可以用,stat前保证该文件没有被打开

可能是你之前写的时候打开了没关，光标定义在文件末尾了 你试试把文件光标定义在开头 ，或者关闭文件