1GETUID(2) Linux Programmer's Manual GETUID(2)
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6 getuid, geteuid - get user identity
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9 #include <unistd.h>
10 #include <sys/types.h>
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12 uid_t getuid(void);
13 uid_t geteuid(void);
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16 getuid() returns the real user ID of the calling process.
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18 geteuid() returns the effective user ID of the calling process.
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21 These functions are always successful.
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24 POSIX.1-2001, POSIX.1-2008, 4.3BSD.
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27 History
28 In UNIX V6 the getuid() call returned (euid << 8) + uid. UNIX V7
29 introduced separate calls getuid() and geteuid().
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31 The original Linux getuid() and geteuid() system calls supported only
32 16-bit user IDs. Subsequently, Linux 2.4 added getuid32() and
33 geteuid32(), supporting 32-bit IDs. The glibc getuid() and geteuid()
34 wrapper functions transparently deal with the variations across kernel
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37 On Alpha, instead of a pair of getuid() and geteuid() system calls, a
38 single getxuid() system call is provided, which returns a pair of real
39 and effective UIDs. The glibc getuid() and geteuid() wrapper functions
40 transparently deal with this. See syscall(2) for details regarding
41 register mapping.
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44 getresuid(2), setreuid(2), setuid(2), credentials(7)
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47 This page is part of release 5.07 of the Linux man-pages project. A
48 description of the project, information about reporting bugs, and the
49 latest version of this page, can be found at
50 https://www.kernel.org/doc/man-pages/.
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54Linux 2019-03-06 GETUID(2)