fseek(3S)                                               fseek(3S)



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

     SYNOPSIS
          #include <stdio.h>

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

          void rewind (stream)
          FILE *stream;

          long ftell (stream)
          FILE *stream;

     DESCRIPTION
          fseek sets the position of the next input or output
          operation on the stream.  The new position is at the signed
          distance offset bytes from the beginning, the current
          position, or the end of the file, when the value of ptrname
          is 0, 1, or 2, respectively.

          rewind(stream) is equivalent to fseek(stream, 0L, 0), 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 may be either input or output.

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

     SEE ALSO
          lseek(2), fopen(3S), popen(3S), ungetc(3S).

     DIAGNOSTICS
          fseek returns non-zero for improper seeks; otherwise it
          returns zero.  An improper seek can be, for example, an
          fseek done on a file that has not been opened via fopen; in
          particular, fseek may not be used on a terminal or on a file
          opened via popen(3S).

     WARNING
          On  an offset returned by ftell is measured in bytes, and it
          is permissible to seek to positions relative to that offset;
          however, portability to systems other than  requires that an
          offset be used by fseek directly. Arithmetic may not
          meaningfully be performed on such an offset, which is not
          necessarily measured in bytes.



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