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

# explain\_iconv(3)

explain iconv(3) errors

## NAME

explain\_iconv - explain [*iconv*(3)](/iconv/3.md) errors

## SYNOPSIS

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

const char \*explain\_iconv(iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);\
 const char \*explain\_errno\_iconv(int errnum, iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);\
 void explain\_message\_iconv(char \*message, int message\_size, iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);\
 void explain\_message\_errno\_iconv(char \*message, int message\_size, int errnum, iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);

## DESCRIPTION

These functions may be used to obtain explanations for errors returned by the [*iconv*(3)](/iconv/3.md) system call.

### explain\_iconv

const char \*explain\_iconv(iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);

The **explain\_iconv** function is used to obtain an explanation of an error returned by the [*iconv*(3)](/iconv/3.md) system call. The least the message will contain is the value of `strerror(errno)`, but usually it will do much better, and indicate the underlying cause in more detail.

The *errno* global variable will be used to obtain the error value to be decoded.

- *cd*

  The original cd, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbuf*

  The original inbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbytesleft*

  The original inbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbuf*

  The original outbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbytesleft*

  The original outbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- Returns:

  The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

**Note:** This function is **not** thread safe, because it shares a return buffer across all threads, and many other functions in this library.

**Example:** This function is intended to be used in a fashion similar to the following example:

`errno = 0;` `size_t result = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);`\
 `if (result < 0 && errno != 0)`

```
{
```

`fprintf(stderr, "%s\n", explain_iconv(cd, inbuf, inbytesleft, outbuf,` `outbytesleft));`

```
    exit(EXIT_FAILURE);
}
```

The above code example is available pre-packaged as the [*explain\_iconv\_or\_die*(3)](/explain_iconv_or_die/3.md) function.

### explain\_errno\_iconv

const char \*explain\_errno\_iconv(int errnum, iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);

The **explain\_errno\_iconv** function is used to obtain an explanation of an error returned by the [*iconv*(3)](/iconv/3.md) system call. The least the message will contain is the value of `strerror(errno)`, but usually it will do much better, and indicate the underlying cause in more detail.

- *errnum*

  The error value to be decoded, usually obtained from the *errno* global variable just before this function is called. This is necessary if you need to call **any** code between the system call to be explained and this function, because many libc functions will alter the value of *errno*.

- *cd*

  The original cd, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbuf*

  The original inbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbytesleft*

  The original inbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbuf*

  The original outbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbytesleft*

  The original outbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- Returns:

  The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

**Note:** This function is **not** thread safe, because it shares a return buffer across all threads, and many other functions in this library.

**Example:** This function is intended to be used in a fashion similar to the following example:

`errno = 0;` `size_t result = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);`\
 `if (result < 0 && errno != 0)`

```
{
    int err = errno;
```

`fprintf(stderr, "%s\n", explain_errno_iconv(err, cd, inbuf, inbytesleft,` `outbuf, outbytesleft));`

```
    exit(EXIT_FAILURE);
}
```

The above code example is available pre-packaged as the [*explain\_iconv\_or\_die*(3)](/explain_iconv_or_die/3.md) function.

### explain\_message\_iconv

void explain\_message\_iconv(char \*message, int message\_size, iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);

The **explain\_message\_iconv** function is used to obtain an explanation of an error returned by the [*iconv*(3)](/iconv/3.md) system call. The least the message will contain is the value of `strerror(errno)`, but usually it will do much better, and indicate the underlying cause in more detail.

The *errno* global variable will be used to obtain the error value to be decoded.

- *message*

  The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.

- *message\_size*

  The size in bytes of the location in which to store the returned message.

- *cd*

  The original cd, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbuf*

  The original inbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbytesleft*

  The original inbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbuf*

  The original outbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbytesleft*

  The original outbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

**Example:** This function is intended to be used in a fashion similar to the following example:

`errno = 0;` `size_t result = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);`\
 `if (result < 0 && errno != 0)`

```
{
    char message[3000];
```

`explain_message_iconv(message, sizeof(message), cd, inbuf, inbytesleft,` `outbuf, outbytesleft);`

```
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}
```

The above code example is available pre-packaged as the [*explain\_iconv\_or\_die*(3)](/explain_iconv_or_die/3.md) function.

### explain\_message\_errno\_iconv

void explain\_message\_errno\_iconv(char \*message, int message\_size, int errnum, iconv\_t cd, char \*\*inbuf, size\_t \*inbytesleft, char \*\*outbuf, size\_t \*outbytesleft);

The **explain\_message\_errno\_iconv** function is used to obtain an explanation of an error returned by the [*iconv*(3)](/iconv/3.md) system call. The least the message will contain is the value of `strerror(errno)`, but usually it will do much better, and indicate the underlying cause in more detail.

- *message*

  The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.

- *message\_size*

  The size in bytes of the location in which to store the returned message.

- *errnum*

  The error value to be decoded, usually obtained from the *errno* global variable just before this function is called. This is necessary if you need to call **any** code between the system call to be explained and this function, because many libc functions will alter the value of *errno*.

- *cd*

  The original cd, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbuf*

  The original inbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *inbytesleft*

  The original inbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbuf*

  The original outbuf, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

- *outbytesleft*

  The original outbytesleft, exactly as passed to the [*iconv*(3)](/iconv/3.md) system call.

**Example:** This function is intended to be used in a fashion similar to the following example:

`errno = 0;` `size_t result = iconv(cd, inbuf, inbytesleft, outbuf, outbytesleft);`\
 `if (result < 0 && errno != 0)`

```
{
    int err = errno;
    char message[3000];
```

`explain_message_errno_iconv(message, sizeof(message), err, cd, inbuf,` `inbytesleft, outbuf, outbytesleft);`

```
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}
```

The above code example is available pre-packaged as the [*explain\_iconv\_or\_die*(3)](/explain_iconv_or_die/3.md) function.

## SEE ALSO

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

  perform character set conversion

- [*explain\_iconv\_or\_die*(3)](/explain_iconv_or_die/3.md)

  perform character set conversion and report errors

## COPYRIGHT

libexplain version 1.4\
 Copyright (C) 2013 Peter Miller