geteuid3p
Get the effective user id
Usage
#include <unistd.h>
uid_t geteuid(void);
Prolog
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
Overview
The geteuid() function shall return the effective user ID of the calling process. The geteuid() function shall not modify errno.
Return value
The geteuid() function shall always be successful and no return value is reserved to indicate an error.
Errors
No errors are defined.
The following sections are informative.
Examples
None.
Application usage
None.
Rationale
In a conforming environment, geteuid() will always succeed. It is possible for implementations to provide an extension where a process in a non-conforming environment will not be associated with a user or group ID. It is recommended that such implementations return (uid_t)-1 and set errno to indicate such an environment; doing so does not violate this standard, since such an environment is already an extension.
Future directions
None.