ungetc - push byte back into input stream
int ungetc(int c, FILE *stream);
The ungetc() function pushes the byte specified by c (con-
verted to an unsigned char) back onto the input stream
pointed to by stream. The pushed-back bytes will be returned
by subsequent reads on that stream in the reverse order of
their pushing. A successful intervening call (with the
stream pointed to by stream) to a file-positioning function
( fseek(3C), fsetpos(3C) or rewind(3C)) discards any
pushed-back bytes for the stream. The external storage
corresponding to the stream is unchanged.
Four bytes of push-back are guaranteed. If ungetc() is
called too many times on the same stream without an inter-
vening read or file-positioning operation on that stream,
the operation may fail.
If the value of c equals that of the macro EOF, the opera-
tion fails and the input stream is unchanged.
A successful call to ungetc() clears the end-of-file indica-
tor for the stream. The value of the file-position indicator
for the stream after reading or discarding all pushed-back
bytes will be the same as it was before the bytes were
pushed back. The file-position indicator is decremented by
each successful call to ungetc(); if its value was 0 before
a call, its value is indeterminate after the call.
Upon successful completion, ungetc() returns the byte pushed
back after conversion. Otherwise it returns EOF.
No errors are defined.
See attributes(5) for descriptions of the following attri-
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | MT-Safe |
read(2), intro(3), fseek(3C), fsetpos(3C), getc(3C),
setbuf(3C), stdio(3C), attributes(5)
Man(1) output converted with