setlocale(3) Library Functions Manual setlocale(3) setlocale - (libc -lc) #include char *setlocale(int category, const char *_Nullable locale); setlocale() . locale (NULL) . category . LC_ALL LC_ADDRESS (*) LC_COLLATE LC_CTYPE LC_IDENTIFICATION (*) LC_MEASUREMENT ( ) (*) LC_MESSAGES LC_MONETARY LC_NAME (*) LC_NUMERIC LC_PAPER (*) LC_TELEPHONE (*) LC_TIME GNU. locale(7). locale category. "C" "da_DK" ( ) setlocale(). locale "" . . glibc ( category) LC_ALL ( ) LANG. . setlocale() NULL. "C" "POSIX" . language[_territory][.codeset][@modifier] language ISO 639 territory ISO 3166 codeset ISO-8859-1 UTF-8. "locale -a" ( locale(1)). locale NULL . "C" . : setlocale(LC_ALL, ""); : o localeconv(3) o MB_CUR_MAX > 1 o strcoll(3) strxfrm(3) o wcscoll(3) wcsxfrm(3) . setlocale() . . . NULL . attributes(7). +----+------------------------------------+----------------------------+ || | | +----+------------------------------------+----------------------------+ |setlocale()| | MT-Unsafe const:locale env | | | | | +----+------------------------------------+----------------------------+ C11, POSIX.1-2008. LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME C11, POSIX.1-2008. LC_MESSAGES POSIX.1-2008. : GNU. POSIX.1-2001 C89. LC_ALL LC_COLLATE LC_CTYPE LC_MONETARY LC_NUMERIC LC_TIME C89, POSIX.1-2001. LC_MESSAGES POSIX.1-2001. : GNU. locale(1), localedef(1), isalpha(3), localeconv(3), nl_langinfo(3), rpmatch(3), strcoll(3), strftime(3), charsets(7), locale(7) 3 . . : . 6.18 8 2026 setlocale(3)