David Rowley <dgrowle...@gmail.com> writes: > On Fri, 18 Jul 2025 at 23:12, Peter Eisentraut <pe...@eisentraut.org> wrote: >> Note that gcc and clang switched to C11 by default a long time ago >> (gcc-5 and clang-3.6), so for most users all these tests won't need to >> do anything. If you want to test it, you could simulate an older >> default like >> ./configure CC='gcc -std=c99'
> On Linux, doing a bit more testing using meson and clang, I tried with > CC=clang CFLAGS=-std=c99 . I get: Note that that's not what Peter suggested. That leads to > FAILED: src/backend/parser/parser.a.p/meson-generated_.._gram.c.o > clang -Isrc/backend/parser/parser.a.p -Isrc/backend/parser > -I../src/backend/parser -Isrc/include -I../src/include > -I/usr/include/libxml2 -fdiagnostics-color=always > -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -O2 -g -std=gnu11 ^^^^^^^^^^ > -fno-strict-aliasing -fwrapv -fexcess-precision=standard -D_GNU_SOURCE > -Wmissing-prototypes -Wpointer-arith -Werror=vla > -Werror=unguarded-availability-new -Wendif-labels > -Wmissing-format-attribute -Wcast-function-type -Wformat-security > -Wdeclaration-after-statement -Wmissing-variable-declarations > -Wno-unused-command-line-argument -Wno-compound-token-split-by-macro > -Wno-format-truncation -Wno-cast-function-type-strict -std=c99 -fPIC ^^^^^^^^ > -pthread -DBUILDING_DLL -MD -MQ > src/backend/parser/parser.a.p/meson-generated_.._gram.c.o -MF > src/backend/parser/parser.a.p/meson-generated_.._gram.c.o.d -o > src/backend/parser/parser.a.p/meson-generated_.._gram.c.o -c > src/backend/parser/gram.c Apparently we are not being too consistent about the order of user-specified CFLAGS versus ones added by configuration? The configuration test must have put the user CFLAGS first. > Strangely, if I swap the order of the c11_test_args so the test tries > and uses -std=c11 first, it works ok. That is indeed weird. regards, tom lane