From 69194b1e9d391a3717c4eabff7de0b5dab932aae Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 8 Dec 2025 18:19:59 -0500 Subject: [PATCH v4 2/2] Support "j" length modifier in snprintf.c. POSIX has for a long time defined the "j" length modifier for printf conversions as meaning the size of intmax_t or uintmax_t. We got away without supporting that so far, but there are good reasons to start doing so now: * On some platforms, defines PRIdMAX as "jd", so that snprintf.c falls over if that is used. * Commit e6be84356 re-introduced upstream's use of PRIdMAX into zic.c. (We hadn't noticed yet because it would only become apparent if bad data was fed to zic, resulting in an error report.) We could revert that decision from our copy of zic.c, but on the whole it seems better to update snprintf.c to support this standard modifier. There might well be extensions, now or in future, that expect it to work. I did this in the lazy man's way of translating "j" to either "l" or "ll" depending on a compile-time sizeof() check, just as was done long ago to support "z" for size_t. One could imagine promoting intmax_t to have full support in snprintf.c, for example converting fmtint()'s value argument and internal arithmetic to use [u]intmax_t not [unsigned] long long. But that'd be more work and I'm hesitant to do it anyway: if there are any platforms out there where intmax_t is actually wider than "long long", this would doubtless result in a noticeable speed penalty to snprintf(). Let's not go there until we have positive evidence that there's a reason to, and some way to measure what size of penalty we're taking. --- configure | 33 +++++++++++++++++++++++++++++++++ configure.ac | 1 + meson.build | 1 + src/include/pg_config.h.in | 3 +++ src/port/snprintf.c | 18 ++++++++++++++++++ 5 files changed, 56 insertions(+) diff --git a/configure b/configure index 3a0ed11fa8e..aaabe2aff70 100755 --- a/configure +++ b/configure @@ -16811,6 +16811,39 @@ cat >>confdefs.h <<_ACEOF _ACEOF +# The cast to long int works around a bug in the HP C Compiler +# version HP92453-01 B.11.11.23709.GP, which incorrectly rejects +# declarations like `int a3[[(sizeof (unsigned char)) >= 0]];'. +# This bug is HP SR number 8606223364. +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking size of intmax_t" >&5 +$as_echo_n "checking size of intmax_t... " >&6; } +if ${ac_cv_sizeof_intmax_t+:} false; then : + $as_echo_n "(cached) " >&6 +else + if ac_fn_c_compute_int "$LINENO" "(long int) (sizeof (intmax_t))" "ac_cv_sizeof_intmax_t" "$ac_includes_default"; then : + +else + if test "$ac_cv_type_intmax_t" = yes; then + { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5 +$as_echo "$as_me: error: in \`$ac_pwd':" >&2;} +as_fn_error 77 "cannot compute sizeof (intmax_t) +See \`config.log' for more details" "$LINENO" 5; } + else + ac_cv_sizeof_intmax_t=0 + fi +fi + +fi +{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_sizeof_intmax_t" >&5 +$as_echo "$ac_cv_sizeof_intmax_t" >&6; } + + + +cat >>confdefs.h <<_ACEOF +#define SIZEOF_INTMAX_T $ac_cv_sizeof_intmax_t +_ACEOF + + # Determine memory alignment requirements for the basic C data types. diff --git a/configure.ac b/configure.ac index c2413720a18..c3c072e9ec7 100644 --- a/configure.ac +++ b/configure.ac @@ -1981,6 +1981,7 @@ AC_CHECK_SIZEOF([void *]) AC_CHECK_SIZEOF([size_t]) AC_CHECK_SIZEOF([long]) AC_CHECK_SIZEOF([long long]) +AC_CHECK_SIZEOF([intmax_t]) # Determine memory alignment requirements for the basic C data types. diff --git a/meson.build b/meson.build index 6e7ddd74683..6a9c70bede6 100644 --- a/meson.build +++ b/meson.build @@ -1775,6 +1775,7 @@ cdata.set('SIZEOF_LONG', cc.sizeof('long', args: test_c_args)) cdata.set('SIZEOF_LONG_LONG', cc.sizeof('long long', args: test_c_args)) cdata.set('SIZEOF_VOID_P', cc.sizeof('void *', args: test_c_args)) cdata.set('SIZEOF_SIZE_T', cc.sizeof('size_t', args: test_c_args)) +cdata.set('SIZEOF_INTMAX_T', cc.sizeof('intmax_t', args: test_c_args)) # Check if __int128 is a working 128 bit integer type, and if so diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index b0b0cfdaf79..72434ce957e 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -645,6 +645,9 @@ RELSEG_SIZE requires an initdb. */ #undef RELSEG_SIZE +/* The size of `intmax_t', as computed by sizeof. */ +#undef SIZEOF_INTMAX_T + /* The size of `long', as computed by sizeof. */ #undef SIZEOF_LONG diff --git a/src/port/snprintf.c b/src/port/snprintf.c index 6541182df6d..d914547fae2 100644 --- a/src/port/snprintf.c +++ b/src/port/snprintf.c @@ -563,6 +563,15 @@ nextch2: else longflag = 1; goto nextch2; + case 'j': +#if SIZEOF_INTMAX_T == SIZEOF_LONG + longflag = 1; +#elif SIZEOF_INTMAX_T == SIZEOF_LONG_LONG + longlongflag = 1; +#else +#error "cannot find integer type of the same size as intmax_t" +#endif + goto nextch2; case 'z': #if SIZEOF_SIZE_T == SIZEOF_LONG longflag = 1; @@ -826,6 +835,15 @@ nextch1: else longflag = 1; goto nextch1; + case 'j': +#if SIZEOF_INTMAX_T == SIZEOF_LONG + longflag = 1; +#elif SIZEOF_INTMAX_T == SIZEOF_LONG_LONG + longlongflag = 1; +#else +#error "cannot find integer type of the same size as intmax_t" +#endif + goto nextch1; case 'z': #if SIZEOF_SIZE_T == SIZEOF_LONG longflag = 1; -- 2.43.7