Provided by: libexplain-dev_1.4.D001-13_amd64 
NAME
explain_setregid - explain setregid(2) errors
SYNOPSIS
#include <libexplain/setregid.h>
const char *explain_setregid(gid_t rgid, gid_t egid);
const char *explain_errno_setregid(int errnum, gid_t rgid, gid_t egid);
void explain_message_setregid(char *message, int message_size, gid_t rgid, gid_t egid);
void explain_message_errno_setregid(char *message, int message_size, int errnum, gid_t
rgid, gid_t egid);
DESCRIPTION
These functions may be used to obtain explanations for errors returned by the setregid(2)
system call.
explain_setregid
const char *explain_setregid(gid_t rgid, gid_t egid);
The explain_setregid function is used to obtain an explanation of an error returned by the
setregid(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.
rgid The original rgid, exactly as passed to the setregid(2) system call.
egid The original egid, exactly as passed to the setregid(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 (setregid(rgid, egid) < 0)
{
fprintf(stderr, "%s\n", explain_setregid(rgid, egid));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_setregid_or_die(3)
function.
explain_errno_setregid
const char *explain_errno_setregid(int errnum, gid_t rgid, gid_t egid);
The explain_errno_setregid function is used to obtain an explanation of an error returned
by the setregid(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.
rgid The original rgid, exactly as passed to the setregid(2) system call.
egid The original egid, exactly as passed to the setregid(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 (setregid(rgid, egid) < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_setregid(err, rgid, egid));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_setregid_or_die(3)
function.
explain_message_setregid
void explain_message_setregid(char *message, int message_size, gid_t rgid, gid_t egid);
The explain_message_setregid function is used to obtain an explanation of an error
returned by the setregid(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.
rgid The original rgid, exactly as passed to the setregid(2) system call.
egid The original egid, exactly as passed to the setregid(2) system call.
Example: This function is intended to be used in a fashion similar to the following
example:
if (setregid(rgid, egid) < 0)
{
char message[3000];
explain_message_setregid(message, sizeof(message), rgid, egid);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_setregid_or_die(3)
function.
explain_message_errno_setregid
void explain_message_errno_setregid(char *message, int message_size, int errnum, gid_t
rgid, gid_t egid);
The explain_message_errno_setregid function is used to obtain an explanation of an error
returned by the setregid(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.
rgid The original rgid, exactly as passed to the setregid(2) system call.
egid The original egid, exactly as passed to the setregid(2) system call.
Example: This function is intended to be used in a fashion similar to the following
example:
if (setregid(rgid, egid) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_setregid(message, sizeof(message), err, rgid, egid);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_setregid_or_die(3)
function.
SEE ALSO
setregid(2)
set real and/or effective group ID
explain_setregid_or_die(3)
set real and/or effective group ID and report errors
COPYRIGHT
libexplain version 1.4
Copyright (C) 2012 Peter Miller
explain_setregid(3)