fopen文件追加的问题

[rotApple]

怎么样往文件的前面追加? 而不是往最后面追加?

[rotApple]

已经解决!

#include <stdlib.h>
#include <stdio.h>

void showpos(FILE *stream);

int main(void)
{
FILE *stream;
fpos_t filepos;

/* open a file for update */
stream = fopen("DUMMY.FIL", "w+");

/* save the file pointer position */
fgetpos(stream, &filepos);

/* write some data to the file */
fprintf(stream, "This is a test");

/* show the current file position */
showpos(stream);

/* set a new file position, display it */
if (fsetpos(stream, &filepos) == 0)
showpos(stream);
else
{
fprintf(stderr, "Error setting file \
pointer.\n");
exit(1);
}

/* close the file */
fclose(stream);
return 0;
}

void showpos(FILE *stream)
{
fpos_t pos;

/* display the current file pointer
position of a stream */
fgetpos(stream, &pos);
printf("File position: %ld\n", pos);
}



谢谢各位.

[id_oyou]

可以先另存一下文件，再重写文件，只要最后加上刚才另存的原来文件应该就可以了。

[unicode]

DWORD SetFilePointer(
HANDLE hFile,
LONG lDistanceToMove,
PLONG lpDistanceToMoveHigh,
DWORD dwMoveMethod
);

dwMoveMethod:
FILE_BEGIN Indicates that the starting point is zero or the beginning of the file.
FILE_CURRENT Indicates that the starting point is the current value of the file pointer.
FILE_END

[rotApple]

那如果该文本文件原内容爆大不就挂掉了, 这个方法简单,但不好,也不实用.

[rotApple]

DWORD SetFilePointer(
HANDLE hFile,


如果是fopen的话怎么取得hFile?

[xdljf]

文件在硬盘上是顺序存放的,在前面追加有两种方式:
1.不改变文件的内容,把文件记录信息向前移
2.把文件的内容向后移,插入追加的信息,文件记录信息不变

第一种方式OS很难实现的哦

[rotApple]

unicode(衣不如新，人不如故) ( ) 信誉：100 2007-08-02 10:57:53 得分: 0


DWORD SetFilePointer(
HANDLE hFile,
LONG lDistanceToMove,
PLONG lpDistanceToMoveHigh,
DWORD dwMoveMethod
);

dwMoveMethod:
FILE_BEGIN Indicates that the starting point is zero or the beginning of the file.
FILE_CURRENT Indicates that the starting point is the current value of the file pointer.
FILE_END


===================================================


他的这个应该是可行的, 只是用fopen后怎么得到打开的文件的句柄??

[unicode]

先打开得到handle，然后再set不可以吗

[fantasyemperor]

SetFilePointer 使用的是CreateFile产生的句柄

[rotApple]

FILE* pf = fopen(path,_T("a+"));

这返回的是FILE指针啊. 不是HANDLE