NetBSD enables -Wcast-qual when building its localtime.c. * Makefile (GCC_DEBUG_FLAGS): Add -Wcast-qual. * localtime.c (TYPECVT, UNCONST): New macros. (tzname) [2 <= HAVE_TZNAME + TZ_TIME_T]: (update_tzname_etc, settzname, localsub, gmtsub): Use UNCONST instead of casting to char *. --- Makefile | 3 ++- localtime.c | 31 ++++++++++++++++++++++--------- 2 files changed, 24 insertions(+), 10 deletions(-) diff --git a/Makefile b/Makefile index f1ce7abb..2130582c 100644 --- a/Makefile +++ b/Makefile @@ -320,7 +320,8 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \ $(GCC_INSTRUMENT) \ -Wall -Wextra \ -Walloc-size-larger-than=100000 -Warray-bounds=2 \ - -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wdate-time \ + -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wcast-qual \ + -Wdate-time \ -Wdeclaration-after-statement -Wdouble-promotion \ -Wduplicated-branches -Wduplicated-cond -Wflex-array-member-not-at-end \ -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \ diff --git a/localtime.c b/localtime.c index 441c5edd..9c185e66 100644 --- a/localtime.c +++ b/localtime.c @@ -37,6 +37,22 @@ static int lock(void) { return 0; } static void unlock(void) { } #endif +/* Convert to TYPE the value of the expression EXPR. Use C99+ implicit + conversion if available, as it is less powerful and therefore safer. */ +#if PORT_TO_C89 +# define TYPECVT(type, expr) ((type) (expr)) +#else +# define TYPECVT(type, expr) ((type) {expr}) +#endif + +/* Unless intptr_t is missing, pacify gcc -Wcast-qual on char const * exprs. + This is a macro so that it can be used in static initializers. */ +#ifdef INTPTR_MAX +# define UNCONST(a) ((char *) (intptr_t) TYPECVT (char const *, a)) +#else +# define UNCONST(a) TYPECVT (char const *, a) +#endif + /* A signed type wider than int, so that we can add 1900 + tm_mon/12 to tm_year without overflow. The static_assert checks that it is indeed wider than int; if this fails on your platform please let us know. */ @@ -290,10 +306,7 @@ static struct tm tm; #endif # if 2 <= HAVE_TZNAME + TZ_TIME_T -char * tzname[2] = { - (char *) wildabbr, - (char *) wildabbr -}; +char *tzname[2] = { UNCONST(wildabbr), UNCONST(wildabbr) }; # endif # if 2 <= USG_COMPAT + TZ_TIME_T long timezone; @@ -378,7 +391,7 @@ static void update_tzname_etc(struct state const *sp, struct ttinfo const *ttisp) { # if HAVE_TZNAME - tzname[ttisp->tt_isdst] = (char *) &sp->chars[ttisp->tt_desigidx]; + tzname[ttisp->tt_isdst] = UNCONST(&sp->chars[ttisp->tt_desigidx]); # endif # if USG_COMPAT if (!ttisp->tt_isdst) @@ -419,7 +432,7 @@ settzname(void) int stddst_mask = 0; # if HAVE_TZNAME - tzname[0] = tzname[1] = (char *) (sp ? wildabbr : utc); + tzname[0] = tzname[1] = UNCONST(sp ? wildabbr : utc); stddst_mask = 3; # endif # if USG_COMPAT @@ -1657,7 +1670,7 @@ localsub(struct state const *sp, time_t const *timep, int_fast32_t setname, if (result) { result->tm_isdst = ttisp->tt_isdst; # ifdef TM_ZONE - result->TM_ZONE = (char *) &sp->chars[ttisp->tt_desigidx]; + result->TM_ZONE = UNCONST(&sp->chars[ttisp->tt_desigidx]); # endif if (setname) update_tzname_etc(sp, ttisp); @@ -1725,8 +1738,8 @@ gmtsub(ATTRIBUTE_MAYBE_UNUSED struct state const *sp, time_t const *timep, ** "+xx" or "-xx" if offset is non-zero, ** but this is no time for a treasure hunt. */ - tmp->TM_ZONE = ((char *) - (offset ? wildabbr : gmtptr ? gmtptr->chars : utc)); + tmp->TM_ZONE = UNCONST(offset ? wildabbr + : gmtptr ? gmtptr->chars : utc); #endif /* defined TM_ZONE */ return result; } -- 2.47.1