UNGETC(3)                      Library Routines                      UNGETC(3)




NAME

       ungetc - un-get character from input stream


SYNOPSIS

       #include <stdio.h>

       int ungetc (int c, FILE *stream);


DESCRIPTION

       The  ungetc  function  pushes the character c (converted to an unsigned
       char) back onto the input stream pointed to  by  stream.   The  pushed-
       backed  characters  will  be returned by subsequent reads on the stream
       (in reverse order).  A successful  intervening  call,  using  the  same
       stream,  to one of the file positioning functions fseek(3), fsetpos(3),
       or rewind(3) will discard the pushed back characters.

       One character of push-back is guaranteed, but as long as there is  suf-
       ficient  memory, an effectively infinite amount of pushback is allowed.

       If a character is successfully pushed-back, the  end-of-file  indicator
       for the stream is cleared.


RETURN VALUES

       The ungetc function returns the character pushed-back after the conver-
       sion, or EOF if the operation fails.  If the value of  the  argument  c
       character  equals  EOF,  the  operation  will  fail and the stream will
       remain unchanged.


SEE ALSO

       getc(3), fseek(3), setvbuf(3)


STANDARDS

       The ungetc function conforms to ANSI/C.



GNO                            15 September 1997                     UNGETC(3)

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