getuid man page


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


#include <unistd.h>

uid_t getuid(void);


The getuid() function shall return the real user ID of the calling process.

Return Value

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.


Setting the Effective User ID to the Real User ID

The following example sets the effective user ID and the real user ID of the current process to the real user ID of the caller.

#include <unistd.h>
#include <sys/types.h>
setreuid(getuid(), getuid());

See Also

getegid(), geteuid(), getgid(), setegid(), seteuid(), setgid(), setregid(), setreuid(), setuid()

The Base Definitions volume of POSIX.1‐2008, <sys_types.h>, <unistd.h>


2013 IEEE/The Open Group POSIX Programmer's Manual