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  re‐
       main unchanged.

SEE ALSO

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

STANDARDS

       The ungetc function conforms to ANSI/C.



GNO                            15 September 1997                     UNGETC(3)