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

# explain\_acl\_to\_text(3)

explain acl\_to\_text(3) errors

## NAME

explain\_acl\_to\_text - explain [*acl\_to\_text*(3)](/acl_to_text/3.md) errors

## SYNOPSIS

\#include \<libexplain/acl\_to\_text.h\>

const char \*explain\_acl\_to\_text(acl\_t acl, ssize\_t \*len\_p);\
 const char \*explain\_errno\_acl\_to\_text(int errnum, acl\_t acl, ssize\_t \*len\_p);\
 void explain\_message\_acl\_to\_text(char \*message, int message\_size, acl\_t acl, ssize\_t \*len\_p);\
 void explain\_message\_errno\_acl\_to\_text(char \*message, int message\_size, int errnum, acl\_t acl, ssize\_t \*len\_p);

## DESCRIPTION

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

### explain\_acl\_to\_text

const char \*explain\_acl\_to\_text(acl\_t acl, ssize\_t \*len\_p);

The **explain\_acl\_to\_text** function is used to obtain an explanation of an error returned by the [*acl\_to\_text*(3)](/acl_to_text/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.

- *acl*

  The original acl, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/3.md) system call.

- *len\_p*

  The original len\_p, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/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:

`char *result = acl_to_text(acl, len_p);`\
 `if (!result)`

```
{
```

`fprintf(stderr, "%s\n", explain_acl_to_text(acl, len_p));`

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

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

### explain\_errno\_acl\_to\_text

const char \*explain\_errno\_acl\_to\_text(int errnum, acl\_t acl, ssize\_t \*len\_p);

The **explain\_errno\_acl\_to\_text** function is used to obtain an explanation of an error returned by the [*acl\_to\_text*(3)](/acl_to_text/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*.

- *acl*

  The original acl, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/3.md) system call.

- *len\_p*

  The original len\_p, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/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:

`char *result = acl_to_text(acl, len_p);`\
 `if (!result)`

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

`fprintf(stderr, "%s\n", explain_errno_acl_to_text(err, acl, len_p));`

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

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

### explain\_message\_acl\_to\_text

void explain\_message\_acl\_to\_text(char \*message, int message\_size, acl\_t acl, ssize\_t \*len\_p);

The **explain\_message\_acl\_to\_text** function is used to obtain an explanation of an error returned by the [*acl\_to\_text*(3)](/acl_to_text/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.

- *acl*

  The original acl, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/3.md) system call.

- *len\_p*

  The original len\_p, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/3.md) system call.

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

`char *result = acl_to_text(acl, len_p);`\
 `if (!result)`

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

`explain_message_acl_to_text(message, sizeof(message), acl, len_p);`

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

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

### explain\_message\_errno\_acl\_to\_text

void explain\_message\_errno\_acl\_to\_text(char \*message, int message\_size, int errnum, acl\_t acl, ssize\_t \*len\_p);

The **explain\_message\_errno\_acl\_to\_text** function is used to obtain an explanation of an error returned by the [*acl\_to\_text*(3)](/acl_to_text/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*.

- *acl*

  The original acl, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/3.md) system call.

- *len\_p*

  The original len\_p, exactly as passed to the [*acl\_to\_text*(3)](/acl_to_text/3.md) system call.

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

`char *result = acl_to_text(acl, len_p);`\
 `if (!result)`

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

`explain_message_errno_acl_to_text(message, sizeof(message), err, acl,` `len_p);`

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

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

## SEE ALSO

- [*acl\_to\_text*(3)](/acl_to_text/3.md)

  convert an ACL to text

- [*explain\_acl\_to\_text\_or\_die*(3)](/explain_acl_to_text_or_die/3.md)

  convert an ACL to text and report errors

## COPYRIGHT

libexplain version 1.4\
 Copyright (C) 2013 Peter Miller