llseek man page
_llseek — reposition read/write file offset
#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);
Note: There is no glibc wrapper for this system call; see Notes.
The _llseek() function repositions the offset of the open file description associated with the file descriptor fd to (offset_high<<32) | offset_low bytes 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. It returns the resulting file position in the argument result.
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.
This function is Linux-specific, and should not be used in programs intended to be portable.
Glibc does not provide a wrapper for this system call. To invoke it directly, use syscall(2). However, you probably want to use the lseek(2) wrapper function instead.
lseek(2), open(2), lseek64(3)
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lseek64(3), syscall(2), syscalls(2).
_llseek(2) is an alias of llseek(2).