lseek(2)                                                           lseek(2)


   NAME
         lseek - move read/write file pointer

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

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

   DESCRIPTION
         fildes is a file descriptor returned from a creat, open, dup, or
         fcntl system call.  lseek sets the file pointer associated with
         fildes as follows:

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

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

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

         On success, lseek returns the resulting pointer location, as measured
         in bytes from the beginning of the file.  Note that if fildes is a
         remote file descriptor and offset is negative, lseek returns the file
         pointer even if it is negative.

         lseek allows the file pointer to be set beyond the existing data in
         the file. If data are later written at this point, subsequent reads
         in the gap between the previous end of data and the newly written
         data will return bytes of value 0 until data are written into the
         gap.

         lseek fails and the file pointer remains unchanged if one or more of
         the following are true:

         EBADF          fildes is not an open file descriptor.

         ESPIPE         fildes is associated with a pipe or fifo.

         EINVAL         whence is not SEEKSET, SEEKCUR, or SEEKEND.  The
                        process also gets a SIGSYS signal.

         EINVAL         fildes is not a remote file descriptor, and the
                        resulting file pointer would be negative.

         Some devices are incapable of seeking.  The value of the file pointer
         associated with such a device is undefined.





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   lseek(2)                                                           lseek(2)


   SEE ALSO
         creat(2), dup(2), fcntl(2), open(2).

   DIAGNOSTICS
         Upon successful completion, a non-negative integer indicating the
         file pointer value is returned.  Otherwise, a value of -1 is returned
         and errno is set to indicate the error.














































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