C++中的直接文件訪問？

Question

有沒有辦法直接寫入磁盤沒有緩存在c + +？ 目前我使用：

int open(fileout, O_CREATE | O_WRONLY | O_DIRECT); 
FILE *fh = fdopen(fileout_dev, "wb"); 

是否允許這樣做，有跨平臺的庫？

謝謝阿爾曼。

Answer 1

如果你談論的緩衝，那麼你可以使用setbuf或setvbuf

/* setbuf example */ 
#include <stdio.h> 

int main() 
{ 
    char buffer[BUFSIZ]; 
    FILE *pFile1, *pFile2; 

    pFile1=fopen ("myfile.txt","w"); 
    pFile2=fopen ("myfile2.txt","a"); 

    setbuf (pFile1 , buffer); 
    fputs ("This is sent to a buffered stream",pFile1); 
    fflush (pFile1); 

    setbuf (pFile2 , NULL); 
    fputs ("This is sent to an unbuffered stream",pFile2); 

    fclose (pFile1); 
    fclose (pFile2); 

    return 0; 
} 


/* setvbuf example */ 
#include <stdio.h> 

int main() 
{ 
    FILE *pFile; 

    pFile=fopen ("myfile.txt","w"); 

    // _IONBF disables buffering 
    setvbuf (pFile , NULL , _IONBF, 0); 

    // File operations here 

    fclose (pFile); 

    return 0; 
}