---
name: "idna_strerror"
section: "3"
platform: "linux"
package: "libidn"
version: "1.44-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/idna_strerror"
---

# idna\_strerror(3)

API function

## NAME

idna\_strerror - API function

## SYNOPSIS

**#include \<idna.h\>**

**const char \* idna\_strerror(Idna\_rc** *rc***);**

## ARGUMENTS

- Idna\_rc rc

  an **Idna\_rc** return code.

## DESCRIPTION

Convert a return code integer to a text string.  This string can be used to output a diagnostic message to the user.

## IDNA\_SUCCESS

Successful operation.  This value is guaranteed to always be zero, the remaining ones are only guaranteed to hold non-zero values, for logical comparison purposes.

## IDNA\_STRINGPREP\_ERROR

Error during string preparation.

## IDNA\_PUNYCODE\_ERROR

Error during punycode operation.

## IDNA\_CONTAINS\_NON\_LDH

For IDNA\_USE\_STD3\_ASCII\_RULES, indicate that the string contains non-LDH ASCII characters.

## IDNA\_CONTAINS\_MINUS

For IDNA\_USE\_STD3\_ASCII\_RULES, indicate that the string contains a leading or trailing hyphen-minus (U+002D).

## IDNA\_INVALID\_LENGTH

The final output string is not within the (inclusive) range 1 to 63 characters.

## IDNA\_NO\_ACE\_PREFIX

The string does not contain the ACE prefix (for ToUnicode).

## IDNA\_ROUNDTRIP\_VERIFY\_ERROR

The ToASCII operation on output string does not equal the input.

## IDNA\_CONTAINS\_ACE\_PREFIX

The input contains the ACE prefix (for ToASCII).

## IDNA\_ICONV\_ERROR

Character encoding conversion error.

## IDNA\_MALLOC\_ERROR

Could not allocate buffer (this is typically a fatal error).

## IDNA\_DLOPEN\_ERROR

Could not dlopen the libcidn DSO (only used internally in libc).

Return value: Returns a pointer to a statically allocated string containing a description of the error with the return code  *rc* .

## REPORTING BUGS

Report bugs to \<help-libidn@gnu.org\>.\
 General guidelines for reporting bugs: https://www.gnu.org/gethelp/\
 GNU Libidn home page: https://www.gnu.org/software/libidn/

## COPYRIGHT

Copyright © 2002-2026 Simon Josefsson.\
 Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.

## SEE ALSO

The full documentation for **libidn** is maintained as a Texinfo manual.  If the **info** and **libidn** programs are properly installed at your site, the command

-

  **info libidn**

should give you access to the complete manual. As an alternative you may obtain the manual from:

-

  **https://www.gnu.org/software/libidn/manual/**