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Synopsis:
    #include <stdio.h>
    int fseek( FILE *fp, long int offset, int where );

Description:
    The fseek function changes the read/write position of the file specified
    by fp.  This position defines the character that will be read or written
    on the next I/O operation on the file.  The argument fp is a file
    pointer returned by  fopen or  freopen.  The argument offset is the
    position to seek to relative to one of three positions specified by the
    argument where.  Allowable values for where are:

    SEEK_SET
        The new file position is computed relative to the start of the file.
         The value of offset must not be negative.

    SEEK_CUR
        The new file position is computed relative to the current file
        position.  The value of offset may be positive, negative or zero.

    SEEK_END
        The new file position is computed relative to the end of the file.

    The fseek function clears the end-of-file indicator and undoes any
    effects of the  ungetc function on the same file.

    The  ftell function can be used to obtain the current position in the
    file before changing it.  The position can be restored by using the
    value returned by  ftell in a subsequent call to  fseek with the where
    parameter set to SEEK_SET.

Returns:
    The fseek function returns zero if successful, non-zero otherwise.  When
    an error has occurred,  errno contains a value indicating the type of
    error that has been detected.

See Also:
    fgetpos, fopen, fsetpos, ftell

Example:
    The size of a file can be determined by the following example which
    saves and restores the current position of the file.

    #include <stdio.h>

    long int filesize( FILE *fp )
      {
        long int save_pos, size_of_file;

        save_pos = ftell( fp );
        fseek( fp, 0L, SEEK_END );
        size_of_file = ftell( fp );
        fseek( fp, save_pos, SEEK_SET );
        return( size_of_file );
      }

    void main()
      {
        FILE *fp;

        fp = fopen( "file", "r" );
        if( fp != NULL ) {
          printf( "File size=%ld\n", filesize( fp ) );
          fclose( fp );
        }
      }

Classification:
    ANSI

Systems:
    All