namespace: unchecked return value from library

fix:

CID 1237553 (#1 of 6): Unchecked return value from library
(CHECKED_RETURN

CID 1237553 (#3 of 6): Unchecked return value from library
(CHECKED_RETURN)

CID 1237553 (#4 of 6): Unchecked return value from library
(CHECKED_RETURN)

CID 1237553 (#5 of 6): Unchecked return value from library
(CHECKED_RETURN

CID 1237553 (#6 of 6): Unchecked return value from library
(CHECKED_RETURN)