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llseek(2) [sunos man page]

llseek(2)							   System Calls 							 llseek(2)

NAME
llseek - move extended read/write file pointer SYNOPSIS
#include <sys/types.h> #include <unistd.h> offset_t llseek(int fildes, offset_t offset, int whence); DESCRIPTION
The llseek() function sets the 64-bit extended file pointer associated with the open file descriptor specified by fildes as follows: o If whence is SEEK_SET, the pointer is set to offset bytes. o If whence is SEEK_CUR, the pointer is set to its current location plus offset. o If whence is SEEK_END, the pointer is set to the size of the file plus offset. Although each file has a 64-bit file pointer associated with it, some existing file system types (such as tmpfs) do not support the full range of 64-bit offsets. In particular, on such file systems, non-device files remain limited to offsets of less than two gigabytes. Device drivers may support offsets of up to 1024 gigabytes for device special files. Some devices are incapable of seeking. The value of the file pointer associated with such a device is undefined. RETURN VALUES
Upon successful completion, llseek() returns the resulting pointer location as measured in bytes from the beginning of the file. Remote file descriptors are the only ones that allow negative file pointers. Otherwise, -1 is returned, the file pointer remains unchanged, and errno is set to indicate the error. ERRORS
The llseek() function will fail if: EBADF The fildes argument is not an open file descriptor. EINVAL The whence argument is not SEEK_SET, SEEK_CUR, or SEEK_END; the offset argument is not a valid offset for this file system type; or the fildes argument is not a remote file descriptor and the resulting file pointer would be negative. ESPIPE The fildes argument is associated with a pipe or FIFO. SEE ALSO
creat(2), dup(2), fcntl(2), lseek(2), open(2) SunOS 5.10 6 Jan 1999 llseek(2)

Check Out this Related Man Page

LSEEK(2)						      BSD System Calls Manual							  LSEEK(2)

NAME
lseek, seek -- reposition read/write file offset LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> off_t lseek(int fildes, off_t offset, int whence); DESCRIPTION
The lseek() function repositions the offset of the file descriptor fildes to the argument offset according to the directive whence. The argument fildes must be an open file descriptor. lseek() repositions the file pointer fildes as follows: If whence is SEEK_SET, the offset is set to offset bytes. If whence is SEEK_CUR, the offset is set to its current location plus offset bytes. If whence is SEEK_END, the offset is set to the size of the file plus offset bytes. The lseek() function allows the file offset to be set beyond the end of the existing end-of-file of the file. If data is later written at this point, subsequent reads of the data in the gap return bytes of zeros (until data is actually written into the gap). Some devices are incapable of seeking. The value of the pointer associated with such a device is undefined. RETURN VALUES
Upon successful completion, lseek() returns the resulting offset location as measured in bytes from the beginning of the file. Otherwise, a value of -1 is returned and errno is set to indicate the error. ERRORS
lseek() will fail and the file pointer will remain unchanged if: [EBADF] fildes is not an open file descriptor. [EINVAL] whence is not a proper value, or the resulting file offset would be invalid. [ESPIPE] fildes is associated with a pipe, socket, or FIFO. SEE ALSO
dup(2), open(2) STANDARDS
The lseek() function conforms to ISO/IEC 9945-1:1990 (``POSIX.1''). HISTORY
A seek() function appeared in Version 2 AT&T UNIX, later renamed into lseek() for ``long seek'' due to a larger offset argument type. BUGS
This document's use of whence is incorrect English, but is maintained for historical reasons. BSD
April 3, 2010 BSD

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