explain_setgroups

Section: C Library Functions (3) Local index Up

NAME

explain_setgroups - explain setgroups(2) errors

SYNOPSIS

const char *explain_setgroups(size_t data_size, const gid_t *data);
const char *explain_errno_setgroups(int errnum, size_t data_size, const gid_t *data);
void explain_message_setgroups(char *message, int message_size, size_t data_size, const gid_t *data);
void explain_message_errno_setgroups(char *message, int message_size, int errnum, size_t data_size, const gid_t *data);

DESCRIPTION

These functions may be used to obtain explanations for errors returned by the setgroups(2) system call.

explain_setgroups

const char *explain_setgroups(size_t data_size, const gid_t *data);

The explain_setgroups function is used to obtain an explanation of an error returned by the setgroups(2) 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.

data_size: The original data_size, exactly as passed to the setgroups(2) system call.
data: The original data, exactly as passed to the setgroups(2) 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:

if (setgroups(data_size, data) < 0)

fprintf(stderr, "%s\n", explain_setgroups(data_size, data));

    exit(EXIT_FAILURE);
}

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

explain_errno_setgroups

const char *explain_errno_setgroups(int errnum, size_t data_size, const gid_t *data);

The explain_errno_setgroups function is used to obtain an explanation of an error returned by the setgroups(2) 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.
data_size: The original data_size, exactly as passed to the setgroups(2) system call.
data: The original data, exactly as passed to the setgroups(2) 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:

if (setgroups(data_size, data) < 0)

{
    int err = errno;

fprintf(stderr, "%s\n", explain_errno_setgroups(err, data_size, data));

    exit(EXIT_FAILURE);
}

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

explain_message_setgroups

void explain_message_setgroups(char *message, int message_size, size_t data_size, const gid_t *data);

The explain_message_setgroups function is used to obtain an explanation of an error returned by the setgroups(2) 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.
data_size: The original data_size, exactly as passed to the setgroups(2) system call.
data: The original data, exactly as passed to the setgroups(2) system call.

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

if (setgroups(data_size, data) < 0)

{
    char message[3000];

explain_message_setgroups(message, sizeof(message), data_size, data);

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

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

explain_message_errno_setgroups

void explain_message_errno_setgroups(char *message, int message_size, int errnum, size_t data_size, const gid_t *data);

The explain_message_errno_setgroups function is used to obtain an explanation of an error returned by the setgroups(2) 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.
data_size: The original data_size, exactly as passed to the setgroups(2) system call.
data: The original data, exactly as passed to the setgroups(2) system call.

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

if (setgroups(data_size, data) < 0)

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

explain_message_errno_setgroups(message, sizeof(message), err, data_size, data);

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

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

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Index

NAME

SYNOPSIS

DESCRIPTION

explain_setgroups
explain_errno_setgroups
explain_message_setgroups
explain_message_errno_setgroups

SEE ALSO

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This document was created by man2html, using the manual pages.
Time: 21:45:51 GMT, April 16, 2011