_llseek - 重新讀取/寫入檔案偏移量
#include <sys/types.h> #include <unistd.h> int _llseek(unsigned int fd, unsigned long offset_high, unsigned long offset_low, loff_t *result, unsigned int whence); |
The _llseek() function repositions the offset of the open file associated with the file descriptor fd to (offset_high<<32) | offset_low bytes relative to the beginning of the file, the current position in the file, or the end of the file, depending on whether whence is SEEK_SET, SEEK_CUR, or SEEK_END, respectively.
It returns the resulting file position in the argument result.
Upon successful completion, _llseek() returns 0. Otherwise, a value of -1 is returned and errno is set to indicate the error.
標籤 | 描述 |
---|---|
EBADF | fd is not an open file descriptor. |
EFAULT | Problem with copying results to user space. |
EINVAL | whence is invalid. |
這個函式是Linux特有的,應該在旨在是可移植的程式不被使用。
glibc不提供包裝,這個系統呼叫,它呼叫 syscall(2).