lseek(2)                                                           lseek(2)




 NAME    [Toc]    [Back]
      lseek - move read/write file pointer; seek

 SYNOPSIS    [Toc]    [Back]
      #include <unistd.h>

      off_t lseek(int fildes, off_t offset, int whence);

 DESCRIPTION    [Toc]    [Back]
      lseek() sets the file pointer associated with the file descriptor 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.

      These symbolic constants are defined in <unistd.h>.

 RETURN VALUE    [Toc]    [Back]
      When lseek() completes successfully, it returns an integer, which is
      the resulting file offset 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.

      For all files that are not character or block special files, the
      integer returned on successful completion is non-negative.  For
      character or block special files that correspond to disk sections
      larger than 2 gigabytes, a non-negative integer is returned for
      successful seeks beyond 2 gigabytes.  This value is the resulting file
      offset as measured in bytes from the beginning of the file, when taken
      as an unsigned value.  -1 always indicates an error return, even when
      encountered on greater than 2 gigabyte disk sections.  The lseek()
      call succeeds for NFS directories even if the resulting file offset
      becomes negative.

 ERRORS    [Toc]    [Back]
      lseek() fails and the file offset remains unchanged if one or more of
      the following is true:

      [EBADF]        fildes is not an open file descriptor.

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

      [EINVAL]       whence is not one of the supported values.

      [EINVAL]       The resulting file offset would be negative.




 Hewlett-Packard Company            - 1 -   HP-UX 11i Version 2: August 2003






 lseek(2)                                                           lseek(2)




      [EINVAL]       The resulting file offset would be a value which cannot
                     be represented correctly in an object of type off_t.

 WARNINGS    [Toc]    [Back]
      Some devices are incapable of seeking.  The value of the file offset
      associated with such a device is undefined.

      Using lseek() with a whence of SEEK_END on device special files is not
      supported and the results are not defined.

 SEE ALSO    [Toc]    [Back]
      creat(2), dup(2), fcntl(2), lseek64(2), open(2), unistd(5).

 STANDARDS CONFORMANCE    [Toc]    [Back]
      lseek(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1


 Hewlett-Packard Company            - 2 -   HP-UX 11i Version 2: August 2003