geteuid - get the effective user ID
The geteuid() function shall return the effective user ID of the calling process. The geteuid() function shall not modify errno.
The geteuid() function shall always be successful and no return value is reserved to indicate an error.
No errors are defined.
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.
getegid, getgid, getuid, setegid, seteuid, setgid, setregid, setreuid, setuid
XBD <sys/types.h>, <unistd.h>
First released in Issue 1. Derived from Issue 1 of the SVID.
In the SYNOPSIS, the optional include of the <sys/types.h> header is removed.
The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:
POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0158  is applied.
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