HPUX fseek[3s]

 fseek(3S)                                                         fseek(3S)





 NAME
      fseek(), rewind(), ftell() - reposition a file pointer in a stream

 SYNOPSIS
      #include <stdio.h>

      int fseek(FILE *stream, long int offset, int whence);

      void rewind(FILE *stream);

      long int ftell(FILE *stream);

 DESCRIPTION
      fseek() sets the file-position indicator for stream.  The new
      position, measured in bytes from the beginning of the file, is
      obtained by adding offset to the position specified by whence.  The
      specified position is the beginning of the file for SEEK_SET, the
      current position for SEEK_CUR, or end-of-file for SEEK_END.

      If the most recent operation, other than ftell() , on the stream is
      fflush(), the file offset in the underlying open file description is
      adjusted to reflect the location specified by the fseek() .

      rewind(stream) is equivalent to fseek (stream, 0L, SEEK_SET), except
      that no value is returned.

      fseek() and rewind() undo any effects of ungetc(3S).

      After fseek() or rewind(), the next operation on a file opened for
      update can be either input or output.  fseek() clears the EOF
      indicator for the stream.  rewind() does an implicit clearerr() call
      (see ferror(3S)).

      ftell() returns the offset of the current byte relative to the
      beginning of the file associated with the named stream.

 RETURN VALUE
      fseek() returns zero if it succeeds.  Otherwise it returns -1 and sets
      errno to indicate the error.

      ftell() returns the current value of the file position indicator for
      the stream measured in bytes from the beginning of the file.
      Otherwise, ftell() returns -1 and sets errno to indicate the error.

      rewind() does not return a value.  Therefore, any application that
      needs to detect errors should clear errno before calling rewind().
      Then, upon completion, if errno is non-zero, it should assume an error
      has occurred.

 ERRORS
      fseek(), ftell(), and rewind() fail if the stream is unbuffered or the



 Hewlett-Packard Company            - 1 -     HP-UX Release 9.0: August 1992






 fseek(3S)                                                         fseek(3S)





      buffered data needs to be flushed, or if any of the following
      conditions are encountered:

           [EAGAIN]       The O_NONBLOCK flag is set for the file descriptor
                          and the process would be delayed in the write
                          operation.

           [EBADF]        The underlying file is not open for writing.

           [EFBIG]        An attempt was made to write a file that exceeds
                          the process's file size limit or the maximum file
                          size.  See ulimit(2).

           [EINTR]        A signal was caught during the write operation.

           [EIO]          The process is in a background process group and
                          is attempting to write to its controlling
                          terminal, TOSTOP is set, the process is neither
                          ignoring nor blocking the SIGTTOU signal, and the
                          process group of the process is orphaned.

           [ENOSPC]       There was no free space remaining on the device
                          containing the file.

           [EPIPE]        An attempt was made to write to a pipe that is not
                          open for reading by any process.  A SIGPIPE signal
                          is also sent to the process.

           [ESPIPE]       A seek operation was attempted and the file
                          descriptor underlying stream is associated with a
                          pipe.

      fseek() also fails if:

           [EINVAL]       The whence argument is invalid, or the file-
                          position indicator would be set to a negative
                          value.

      Additional errno values may be set by the underlying write() and
      lseek() functions (see write(2) and lseek(2)).

 WARNINGS
      On HP-UX systems, the offset returned by ftell() is measured in bytes
      and it is permissible to seek to positions relative to that offset.
      However, when porting to non-HP-UX systems, fseek() should be used
      directly without relying on any offset obtained from ftell() because
      arithmetic cannot meaningfully be performed on such an offset if it is
      not measured in bytes on a particular operating system.

      fseek() and rewind() have no effect on streams that have been opened
      in append mode (see fopen(3S)).



 Hewlett-Packard Company            - 2 -     HP-UX Release 9.0: August 1992






 fseek(3S)                                                         fseek(3S)





 SEE ALSO
      lseek(2), write(2), ferror(3S), fopen(3S), fgetpos(3S), ungetc(3S).

 STANDARDS CONFORMANCE
      fseek(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C

      ftell(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C

      rewind(): AES, SVID2, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, ANSI C













































 Hewlett-Packard Company            - 3 -     HP-UX Release 9.0: August 1992