lseek(2) [minix man page]

LSEEK(2)							System Calls Manual							  LSEEK(2)

NAME

       lseek - move read/write pointer

SYNOPSIS

       #include <sys/types.h>
       #include <unistd.h>

       #define SEEK_SET  0     /* offset is absolute */
       #define SEEK_CUR  1     /* relative to current position */
       #define SEEK_END  2     /* relative to end of file */

       off_t lseek(int d, off_t offset, int whence)

DESCRIPTION

       The descriptor d refers to a file or device open for reading and/or writing.  Lseek sets the file pointer of d as follows:

	      If whence is SEEK_SET, the pointer is set to offset bytes.

	      If whence is SEEK_CUR, the pointer is set to its current location plus offset.

	      If whence is SEEK_END, the pointer is set to the size of the file plus offset.

       Upon  successful  completion, the resulting pointer location as measured in bytes from beginning of the file is returned.  Some devices are
       incapable of seeking.  The value of the pointer associated with such a device is undefined.

NOTES

       Seeking far beyond the end of a file, then writing, creates a gap or "hole", which occupies no physical space and reads as zeros.

RETURN VALUE

       Upon successful completion, the current file pointer value is returned.	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.

       [ESPIPE]       Fildes is associated with a pipe or a socket.

       [EINVAL]       Whence is not a proper value.

SEE ALSO

       fcntl(2), open(2).

BUGS

       This document's use of whence is incorrect English, but maintained for historical reasons.

4th Berkeley Distribution					 February 24, 1986							  LSEEK(2)

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

NAME

     lseek -- reposition read/write file offset

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.

     [EINVAL]		The seek location (calculated from offset and whence) is negative.

     [EOVERFLOW]	The seek location is too large to be stored in an object of type off_t.

     [ESPIPE]		Fildes is associated with a pipe, socket, or FIFO.

SEE ALSO

     dup(2), open(2)

BUGS

     This document's use of whence is incorrect English, but is maintained for historical reasons.

STANDARDS

     The lseek() function conforms to IEEE Std 1003.1-1988 (``POSIX.1'').

4th Berkeley Distribution					  April 19, 1994					 4th Berkeley Distribution