Return to lseek.2 CVS log

Up to [CSRG BSD Unix] / 43BSDTahoe / man / man2

Annotation of 43BSDTahoe/man/man2/lseek.2, revision 1.1.1.1

1.1       root        1: .\" Copyright (c) 1980 Regents of the University of California.
                      2: .\" All rights reserved.  The Berkeley software License Agreement
                      3: .\" specifies the terms and conditions for redistribution.
                      4: .\"
                      5: .\"    @(#)lseek.2     6.3 (Berkeley) 2/24/86
                      6: .\"
                      7: .TH LSEEK 2 "February 24, 1986"
                      8: .UC 4
                      9: .SH NAME
                     10: lseek \- move read/write pointer
                     11: .SH SYNOPSIS
                     12: .nf
                     13: .ft B
                     14: #include <sys/file.h>
                     15: .PP
                     16: .nf
                     17: .ft B
                     18: .ta 1.25i 1.6i 1.8i
                     19: #define L_SET  0       /* set the seek pointer */
                     20: #define L_INCR 1       /* increment the seek pointer */
                     21: #define L_XTND 2       /* extend the file size */
                     22: .PP
                     23: .ft B
                     24: pos = lseek(d, offset, whence)
                     25: off_t pos;
                     26: int d;
                     27: off_t offset;
                     28: int whence;
                     29: .fi
                     30: .ft R
                     31: .SH DESCRIPTION
                     32: The descriptor 
                     33: .I d
                     34: refers to a file or device open for reading and/or writing.
                     35: .I Lseek
                     36: sets the file pointer of
                     37: .I d
                     38: as follows:
                     39: .IP
                     40: If
                     41: .I whence
                     42: is L_SET, the pointer is set to
                     43: .I offset
                     44: bytes.
                     45: .IP
                     46: If
                     47: .I whence
                     48: is L_INCR, the pointer is set to its current location plus
                     49: .IR offset .
                     50: .IP
                     51: If
                     52: .I whence
                     53: is L_XTND, the pointer is set to the size of the
                     54: file plus
                     55: .IR offset .
                     56: .PP
                     57: Upon successful completion, the resulting pointer location
                     58: as measured in bytes from beginning of the file is returned.
                     59: Some devices are incapable of seeking.  The value of the pointer
                     60: associated with such a device is undefined.
                     61: .SH NOTES
                     62: Seeking far beyond the end of a file, then writing,
                     63: creates a gap or \*(lqhole\*(rq, which occupies no
                     64: physical space and reads as zeros.
                     65: .SH "RETURN VALUE
                     66: Upon successful completion,
                     67: the current file pointer value is returned.
                     68: Otherwise,
                     69: a value of \-1 is returned and \fIerrno\fP is set to indicate
                     70: the error.
                     71: .SH "ERRORS
                     72: .I Lseek
                     73: will fail and the file pointer will remain unchanged if:
                     74: .TP 15
                     75: [EBADF]
                     76: .I Fildes
                     77: is not an open file descriptor.
                     78: .TP 15
                     79: [ESPIPE]
                     80: .I Fildes
                     81: is associated with a pipe or a socket.
                     82: .TP 15
                     83: [EINVAL]
                     84: .I Whence
                     85: is not a proper value.
                     86: .SH "SEE ALSO"
                     87: dup(2), open(2)
                     88: .SH BUGS
                     89: This document's use of
                     90: .I whence
                     91: is incorrect English, but maintained for historical reasons.

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.