getenv(3) Library Functions Manual getenv(3) getenv, secure_getenv - (libc -lc) #include char *getenv(const char *name); char *secure_getenv(const char *name); glibc ( feature_test_macros(7)): secure_getenv(): _GNU_SOURCE getenv() name value . secure_getenv() getenv() NULL " " . : o ( set-user-ID set-group-ID) o o . Linux. secure_getenv() set-user-ID set-group-ID . getenv() NULL . attributes(7). +----------------------+------------------------------------+------------------------------------------------------------------------+ | | | | +----------------------+------------------------------------+------------------------------------------------------------------------+ |getenv(), | | (MT-Safe) | |secure_getenv() | | | +----------------------+------------------------------------+------------------------------------------------------------------------+ getenv() C11, POSIX.1-2008. secure_getenv() POSIX.1-2024. getenv() POSIX.1-2001 C89 C99 SVr4 4.3BSD. secure_getenv() POSIX.1-2024 glibc 2.17. name=value. getenv() . . getenv() . getenv() getenv() putenv(3) setenv(3) unsetenv(3). " " secure_getenv() AT_SECURE . clearenv(3) getauxval(3) putenv(3) setenv(3) unsetenv(3) capabilities(7) environ(7) 3 . . : . 6.18 8 2026 getenv(3)