Provided by: manpages-dev_3.35-0.1ubuntu1_all
getuid, geteuid - get user identity
#include <unistd.h> #include <sys/types.h> uid_t getuid(void); uid_t geteuid(void);
getuid() returns the real user ID of the calling process. geteuid() returns the effective user ID of the calling process. When a normal program is executed, the effective and real user ID of the process are set to the ID of the user executing the file. When a set ID program is executed the real user ID is set to the calling user and the effective user ID corresponds to the set ID bit on the file being executed.
These functions are always successful.
History In UNIX V6 the getuid() call returned (euid << 8) + uid. UNIX V7 introduced separate calls getuid() and geteuid().
The original Linux getuid() and geteuid() system calls supported only 16-bit user IDs. Subsequently, Linux 2.4 added getuid32() and geteuid32(), supporting 32-bit IDs. The glibc getuid() and geteuid() wrapper functions transparently deal with the variations across kernel versions.
getresuid(2), setreuid(2), setuid(2), credentials(7)
This page is part of release 3.35 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://man7.org/linux/man- pages/.