On Fri, Nov 08, 2019 at 04:25:07PM +0000, p...@hermes.cam.ac.uk wrote: > On Thu, 7 Nov 2019, Petr Pisar via Pcre-dev wrote: > > > I can see GCC 4.8.5 prints these warnings on 32-bit PowerPC: > > > > gcc -DHAVE_CONFIG_H -I. -I./src "-I./src" -pthread -O2 -g -pipe -Wall > > -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong > > --param=ssp-buffer-size=4 -grecord-gcc-switches -m32 -mcpu=power7 > > -mtune=power7 -c -o src/pcre2test-pcre2test.o `test -f 'src/pcre2test.c' || > > echo './'`src/pcre2test.c > > [...] > > src/pcre2test.c: In function 'process_pattern': > > src/pcre2test.c:5212:13: warning: format '%lu' expects argument of type > > 'long unsigned int', but argument 3 has type 'int' [-Wformat=] > > "opening quote is at offset %" PTR_FORM ".\n", pq - buffer - > > 2); > > I am going to need some help here. The PTR_FORM macro is set to the > appropriate print format for pointers. It is currently defined like > this: > > /* VC and older compilers don't support %td or %zu, and even some that claim > to > be C99 don't support it (hence DISABLE_PERCENT_ZT). */ > > #if defined(_MSC_VER) || !defined(__STDC_VERSION__) || __STDC_VERSION__ < > 199901L || defined(DISABLE_PERCENT_ZT) > #define PTR_FORM "lu" > #define SIZ_FORM "lu" > #define SIZ_CAST (unsigned long int) > #else > #define PTR_FORM "td" > #define SIZ_FORM "zu" > #define SIZ_CAST > #endif > > I presume you are seeing %lu because gcc 4.8.5 triggers the > __STDC_VERSION__ test.
Yes. GCC 4.8.5 defaults to -std=gnu90 and __STDC_VERSION__ is not defined there. Recent GCC defaults to gnu17 and __STDC_VERSION__ is "201710L". > What is the best way (compatible with 4.8.5) to > test for being in a 32-bit system at preprocessor time? Is > The issue is that 32-bit integers do not mean 32-bit pointers. E.g. MIPS64 n32 ABI and AMD64 x32 ABI have 64-bit integers but 32-bit pointers. GCC provides __SIZEOF_POINTER__ macro, but I don't think there is any standard for that. A portable way requires testing a sizeof() operator output in ./configure script. But that needs executing the compiled code and that would be problem when crosscompiling. > #if LONG_MAX == 2147483647 > > the right way to do it? If so, then PTR_FORM and SIZ_FORM can be defined > as "u" when that test is true. Presumably the cast is OK. > Accordig to my tests with GCC and glibc for Linux, LONG_MAX indicates size of integers correctly. But I don't have any other compilers or platforms available. Web search reveals that some Windows systems (LLP64 model) have long int shorter than a pointer <http://infocenter.arm.com/help/topic/com.arm.doc.dai0490a/ar01s01.html>. Frankly I don't believe there is a way of solving it and I'd just keep the warning there. Using C99 conformant compilers is the correct way. E.g. passing -std=c99 to GCC with glibc fixes the warning. I'd just document it somwehere in README or in source code near the PTR_FORM macro definition. -- Petr
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