1getresuid(2) System Calls Manual getresuid(2)
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6 getresuid, getresgid - get real, effective, and saved user/group IDs
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9 Standard C library (libc, -lc)
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12 #define _GNU_SOURCE /* See feature_test_macros(7) */
13 #include <unistd.h>
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15 int getresuid(uid_t *ruid, uid_t *euid, uid_t *suid);
16 int getresgid(gid_t *rgid, gid_t *egid, gid_t *sgid);
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19 getresuid() returns the real UID, the effective UID, and the saved set-
20 user-ID of the calling process, in the arguments ruid, euid, and suid,
21 respectively. getresgid() performs the analogous task for the
22 process's group IDs.
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25 On success, zero is returned. On error, -1 is returned, and errno is
26 set to indicate the error.
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29 EFAULT One of the arguments specified an address outside the calling
30 program's address space.
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33 None. These calls also appear on HP-UX and some of the BSDs.
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36 Linux 2.1.44, glibc 2.3.2.
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38 The original Linux getresuid() and getresgid() system calls supported
39 only 16-bit user and group IDs. Subsequently, Linux 2.4 added getre‐
40 suid32() and getresgid32(), supporting 32-bit IDs. The glibc getre‐
41 suid() and getresgid() wrapper functions transparently deal with the
42 variations across kernel versions.
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45 getuid(2), setresuid(2), setreuid(2), setuid(2), credentials(7)
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49Linux man-pages 6.04 2023-03-30 getresuid(2)