_llseek - reposition read/write file offset
Standard C library (libc
, -lc
)
#include <sys/syscall.h> /* Definition of SYS_* constants */
#include <unistd.h>
int syscall(SYS__llseek, unsigned int fd, unsigned long offset_high,
unsigned long offset_low, loff_t *result,
unsigned int whence);
Note
: glibc provides no wrapper for
_llseek(), necessitating the use of
syscall(2).
Note: for information about the llseek(3) library function, see lseek64(3).
The _llseek() system call repositions the offset of
the open file description associated with the file descriptor
fd
to the value
(offset_high << 32) | offset_low
This new offset is a byte offset relative to the beginning of the
file, the current file offset, or the end of the file, depending on
whether whence
is SEEK_SET,
SEEK_CUR, or SEEK_END,
respectively.
The new file offset is returned in the argument result
. The
type loff_t
is a 64-bit signed type.
This system call exists on various 32-bit platforms to support seeking to large file offsets.
Upon successful completion, _llseek() returns 0.
Otherwise, a value of -1 is returned and errno
is set to
indicate the error.
fd
is not an open file descriptor.
Problem with copying results to user space.
whence
is invalid.
You probably want to use the lseek(2) wrapper function instead.
Linux.