Hi Eric, Thanks for the pointers.
> The latest draft comments on C go a step further (warning, big document): > https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3091.doc https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3108.doc seems to be the latest one, now. > Searching that for %B finds: > FR-217 > Make %B optional > Accepted with comment: Wording from N 3072 section 15 with editorial > corrections > > so now go check N3072: > https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3072.htm#make-printf-format-specifier-b-optional > > which states that the PRIBPTR in <inttypes.h> is now a reliable witness > of whether %B has C23 semantics rather than other > implementation-defined semantics. > > and glibc has updated their %B implementation accordingly: > https://sourceware.org/git/?p=glibc.git;a=commit;h=2d4728e60621 The implementation could be to define a C macro or AC_SUBSTed variable in gl_PREREQ_VASNPRINTF_DIRECTIVE_UPPERCASE_B and test it in inttypes.in.h. But still, I don't wish to make this change to Gnulib's <inttypes.h> for the moment, because: * Logically, there should also be definitions of PRIbN PRIbLEASTN PRIbFASTN PRIbMAX PRIbPTR in <inttypes.h>, but I do not see them in the latest complete PDF https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3088.pdf section 7.8.1.(3). * These macros are redundant anyway: PRIb8 "w8b" PRIb16 "w16b" PRIb32 "w32b" PRIb64 "w64b" PRIbLEAST8 "w8b" PRIbLEAST16 "w16b" PRIbLEAST32 "w32b" PRIbLEAST64 "w64b" PRIbFAST8 "wf8b" PRIbFAST16 "wf16b" PRIbFAST32 "wf32b" PRIbFAST64 "wf64b" PRIbMAX "jb" and likewise for uppercase B. Bruno
