fsetpos(S)                     6 January 1993                     fsetpos(S)


 Name

    fsetpos - sets the file position indicator for a stream

 Syntax


    cc  . . .  -lc


    #include  <stdio.h>

    int fsetpos(stream, pos)
    FILE *stream;
    const fpos_t *pos;


 Description

    The fsetpos function sets the file position indicator for stream to the
    value of pos, which is obtained in a prior call to fgetpos against
    stream.

    The function clears the end-of-file indicator and undoes any effects of
    the ungetc(stream).  After calling fsetpos, the next operation on stream
    may be either input or output.

 Return value

    If successful, the fsetpos function returns 0.  On failure, the function
    returns a nonzero value and sets errno to one of the following manifest
    constants (defined in stdio.h):

    EBADF     The specified stream is not a valid file handle, or is not
              accessible.

    EINVAL    The stream value is invalid.


 See also

    fgetpos(S)

 Standards conformance

    fsetpos is conformant with:
    ANSI X3.159-1989 Programming Language -- C.

 Example


       #include <stdio.h>

       FILE *stream;
       fpos_t pos[];
       int val;
       char list[100];

       main()
       {
                       /* open file1 */
              if ((stream = fopen ("file1","rb")) == NULL)
                       printf ("Trouble opening file\n");
              else {
                       /* Read some data */
                       fread (list, sizeof(char), 100, stream);
                       /* Save current position */
                       if (fgetpos (stream, &pos) != 0)
                               perror("fgetpos error");
                       /* Read some more */
                       fread (list, sizeof(char), 100, stream);
                       /* Return to saved position */
                       if (fsetpos (stream, &pos) != 0)
                               perror ("fsetpos error");
              }
       }


    This program opens the file named file1 and reads 100 characters. It then
    uses fgetpos to find and save the file position pointer. After performing
    another read, the program calls fsetpos to restore the file pointer to
    the saved position.