---
name: "explain_ungetc_or_die"
section: "3"
platform: "linux"
package: "libexplain-dev"
version: "1.4.D001-16"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/explain_ungetc_or_die"
---

# explain\_ungetc\_or\_die(3)

push a character back to a stream and report errors

## NAME

explain\_ungetc\_or\_die - push a character back to a stream and report errors

## SYNOPSIS

\#include \<libexplain/ungetc.h\>

void explain\_ungetc\_or\_die(int c, FILE \*fp);\
 int explain\_ungetc\_on\_error(int c, FILE \*fp);

## DESCRIPTION

The **explain\_ungetc\_or\_die** function is used to call the [*ungetc*(3)](/ungetc/3.md) system call. On failure an explanation will be printed to *stderr*, obtained from the [*explain\_ungetc*(3)](/explain_ungetc/3.md) function, and then the process terminates by calling `exit(EXIT_FAILURE)`.

The **explain\_ungetc\_on\_error** function is used to call the [*ungetc*(3)](/ungetc/3.md) system call. On failure an explanation will be printed to *stderr*, obtained from the [*explain\_ungetc*(3)](/explain_ungetc/3.md) function, but still returns to the caller.

- *c*

  The c, exactly as to be passed to the [*ungetc*(3)](/ungetc/3.md) system call.

- *fp*

  The fp, exactly as to be passed to the [*ungetc*(3)](/ungetc/3.md) system call.

## RETURN VALUE

The **explain\_ungetc\_or\_die** function only returns on success, see [*ungetc*(3)](/ungetc/3.md) for more information. On failure, prints an explanation and exits, it does not return.

The **explain\_ungetc\_on\_error** function always returns the value return by the wrapped [*ungetc*(3)](/ungetc/3.md) system call.

## EXAMPLE

The **explain\_ungetc\_or\_die** function is intended to be used in a fashion similar to the following example:

```
explain_ungetc_or_die(c, fp);
```

## SEE ALSO

- [*ungetc*(3)](/ungetc/3.md)

  push a character back to a stream

- [*explain\_ungetc*(3)](/explain_ungetc/3.md)

  explain [*ungetc*(3)](/ungetc/3.md) errors

- [*exit*(2)](/exit/2.md)

  terminate the calling process

## COPYRIGHT

libexplain version 1.4\
 Copyright (C) 2010 Peter Miller