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.
getuid — get a real user ID
The getuid() function shall return the real user ID of the calling
process. The getuid() function shall not modify errno.
The getuid() function shall always be successful and no return value is
reserved to indicate the error.
No errors are defined.
The following sections are informative.
The following example sets the effective user ID of the calling process to the
real user ID.
In a conforming environment, getuid() 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(), geteuid(), getgid(),
setegid(), seteuid(), setgid(),
setregid(), setreuid(), setuid()
The Base Definitions volume of POSIX.1‐2017,
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1-2017, Standard for Information Technology -- Portable Operating
System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018
Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html .
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