lseek(2)                                                 lseek(2)



NAME
     lseek - move read/write file pointer

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

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

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

     If whence is 0, the pointer is set to offset bytes.

     If whence is 1, the pointer is set to its current location
     plus offset.

     If whence is 2, the pointer is set to the size of the file
     plus offset.

     In the POSIX environment, the following values are defined
     in <unistd.h> for passing as the value of whence:

          SEEK_SET
               0

          SEEK_CUR
               1

          SEEK_END
               2

     On successful completion, the resulting pointer location, as
     measured in bytes from the beginning of the file, is
     returned.

STATUS MESSAGES AND VALUES
     On 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.

     The lseek program will fail and the file pointer will remain
     unchanged if one or more of the following is true:

     EBADF
          fildes is not an open file descriptor.

     ESPIPE



January 1992                                                    1

lseek(2)                                                 lseek(2)



          fildes is associated with a pipe or FIFO.

     EINVAL
          whence is not 0, 1, or 2.

     EINVAL
          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.

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










































2                                                    January 1992