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 ISO/IEC 9945-1:1990
     (“POSIX.1”).

HISTORY

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