explain_acl_from_text man page

explain_acl_from_text — explain acl_from_text(3) errors

Synopsis

#include <libexplain/acl_from_text.h>

const char *explain_acl_from_text(const char *text);
const char *explain_errno_acl_from_text(int errnum, const char *text);
void explain_message_acl_from_text(char *message, int message_size, const char *text);
void explain_message_errno_acl_from_text(char *message, int message_size, int errnum, const char *text);

Description

These functions may be used to obtain explanations for errors returned by the acl_from_text(3) system call.

explain_acl_from_text

const char *explain_acl_from_text(const char *text);

The explain_acl_from_text function is used to obtain an explanation of an error returned by the acl_from_text(3) 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.

text
The original text, exactly as passed to the acl_from_text(3) 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:

acl_t result = acl_from_text(text);
if (result < 0)

{

fprintf(stderr, "%s\n", explain_acl_from_text(text));

    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_acl_from_text_or_die(3) function.

explain_errno_acl_from_text

const char *explain_errno_acl_from_text(int errnum, const char *text);

The explain_errno_acl_from_text function is used to obtain an explanation of an error returned by the acl_from_text(3) 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.
text
The original text, exactly as passed to the acl_from_text(3) 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:

acl_t result = acl_from_text(text);
if (result < 0)

{
    int err = errno;

fprintf(stderr, "%s\n", explain_errno_acl_from_text(err, text));

    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_acl_from_text_or_die(3) function.

explain_message_acl_from_text

void explain_message_acl_from_text(char *message, int message_size, const char *text);

The explain_message_acl_from_text function is used to obtain an explanation of an error returned by the acl_from_text(3) 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.
text
The original text, exactly as passed to the acl_from_text(3) system call.

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

acl_t result = acl_from_text(text);
if (result < 0)

{
    char message[3000];

explain_message_acl_from_text(message, sizeof(message), text);

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

The above code example is available pre-packaged as the explain_acl_from_text_or_die(3) function.

explain_message_errno_acl_from_text

void explain_message_errno_acl_from_text(char *message, int message_size, int errnum, const char *text);

The explain_message_errno_acl_from_text function is used to obtain an explanation of an error returned by the acl_from_text(3) 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.
text
The original text, exactly as passed to the acl_from_text(3) system call.

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

acl_t result = acl_from_text(text);
if (result < 0)

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

explain_message_errno_acl_from_text(message, sizeof(message), err, text);

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

The above code example is available pre-packaged as the explain_acl_from_text_or_die(3) function.

See Also

acl_from_text(3)
create an ACL from text
explain_acl_from_text_or_die(3)
create an ACL from text and report errors

Referenced By

explain(3), explain_acl_from_text_or_die(3).