GETUID(2)                 FreeBSD System Calls Manual                GETUID(2)

NAME
     getuid, geteuid - get user identification

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     uid_t
     getuid(void);

     uid_t
     geteuid(void);

DESCRIPTION
     The getuid() system call returns the real user ID of the calling process.
     The geteuid() system call returns the effective user ID of the calling
     process.

     The real user ID is that of the user who has invoked the program.  As the
     effective user ID gives the process additional permissions during
     execution of "set-user-ID" mode processes, getuid() is used to determine
     the real-user-id of the calling process.

ERRORS
     The getuid() and geteuid() system calls are always successful, and no
     return value is reserved to indicate an error.

SEE ALSO
     getgid(2), issetugid(2), setgid(2), setreuid(2), setuid(2)

STANDARDS
     The geteuid() and getuid() system calls are expected to conform to IEEE
     Std 1003.1-1990 ("POSIX.1").

HISTORY
     The getuid() function appeared in Version 1 AT&T UNIX.  The geteuid()
     function appeared in Version 4 AT&T UNIX.

FreeBSD 13.1-RELEASE-p6        December 1, 2017        FreeBSD 13.1-RELEASE-p6