---
name: "explain_strtoul_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_strtoul_or_die"
---

# explain\_strtoul\_or\_die(3)

convert string to unsigned long and report errors

## NAME

explain\_strtoul\_or\_die - convert string to unsigned long and report errors

## SYNOPSIS

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

unsigned long explain\_strtoul\_or\_die(const char \*nptr, char \*\*endptr, int base);\
 unsigned long explain\_strtoul\_on\_error(const char \*nptr, char \*\*endptr, int base))

## DESCRIPTION

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

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

- *nptr*

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

- *endptr*

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

- *base*

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

## RETURN VALUE

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

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

## EXAMPLE

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

```
unsigned long result = explain_strtoul_or_die(nptr, endptr, base);
```

## SEE ALSO

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

  convert a string to an unsigned long integer

- [*explain\_strtoul*(3)](/explain_strtoul/3.md)

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

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

  terminate the calling process

## COPYRIGHT

libexplain version 1.4\
 Copyright (C) 2009 Peter Miller