June 4, 1993 UNGETC 3

### NAME

ungetc - un-get character from input stream

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```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 href="../html3/fsetpos.html">fsetpos(3), or rewind(3) (fseek(3), One character of push-back is guaranteed, but as long as there is sufficient 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 conversion, 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

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

### STANDARDS

The ungetc(``) function conforms to ANSI X3.159-1989 (``ANSI C89'') .