Strange compiler behavior with PRIu64 in C++

Asked Oct 09 '18 at 07:12

Active Oct 09 '18 at 07:18

Viewed 910 times

I have some code in my c++ file that looks like this:

#include <cinttypes>
....
LOG_INFO("%s duration: %" PRId64 "\n", tag.c_str(), timestamp);

And it can be compiled successfully with flag -std=c++11.

But it is failed been compiling on another machine with following error:

base/utils.h:68:31: error: expected ‘)’ before ‘PRId64’

unless I add flag -D__STDC_FORMAT_MACROS.

The first machine has

gcc "4.8.5 20150623 (Red Hat 4.8.5-16)",

the other machine has

gcc "4.8.5 20150623 (Red Hat 4.8.5-28)"

and using

touch foo.h ; gcc -E -dM foo.h

got same result expect the version macro.

I'm confused why the second machine needs -D__STDC_FORMAT_MACROS to compile PRId64?

edited Oct 09 '18 at 07:18

asked Oct 09 '18 at 07:12

jasonxia

1

[The notes section in this reference](https://en.cppreference.com/w/cpp/types/integer#Notes) should be helpful. – Some programmer dude Oct 09 '18 at 07:18
Similar question: https://stackoverflow.com/questions/14535556/why-doesnt-priu64-work-in-this-code – Martin Oct 09 '18 at 08:14
Are you sure the GCC version difference is causing this? It looks like more a difference in *other* header files. – Florian Weimer Oct 09 '18 at 08:56
@Martin, I'm using `-std=c++11` so I expected no `-D__STDC_FORMAT_MACROS` needed. – jasonxia Oct 09 '18 at 12:03
@FlorianWeimer, I don't think the GCC version causing this. I have no idea why this happened. – jasonxia Oct 09 '18 at 12:04

0 Answers0