Bug 27610

Summary:	snprintf() is undefined by _XOPEN_SOURCE=500 on BSDs, making poppler 0.12.4 fail to compile.
Product:	poppler	Reporter:	Javier Villavicencio <the_paya>
Component:	general	Assignee:	poppler-bugs <poppler-bugs>
Status:	RESOLVED FIXED	QA Contact:
Severity:	normal
Priority:	medium
Version:	unspecified
Hardware:	x86 (IA32)
OS:	FreeBSD
Whiteboard:
i915 platform:		i915 features:

Description Javier Villavicencio 2010-04-12 20:45:54 UTC

CMake config (autotools too I think, just did a quick grep) is adding the define -D_XOPEN_SOURCE=500 which (at that version, 500) correctly leaves snprintf() undefined, according to the spec.
Given that function is being used in poppler/Catalog.cc, the proper define should be -D_XOPEN_SOURCE=600.

Perhaps unrelated to the summary, but also causing compile to fail here, strcasecmp() is being used in 2 places, poppler/GlobalParams.cc and test/perf-test.cc, this is defined on <strings.h> (on both BSD and Linux), which isn't included in the source files (they only have <string.h>, which seems to be enough for Linux).

Comment 1 Albert Astals Cid 2010-04-13 14:03:35 UTC

Can you point to the spec that says that snprintf shall be undefined when -D_XOPEN_SOURCE=500

I added the strings.h include for strcasecmp

Comment 2 Javier Villavicencio 2010-04-13 15:32:38 UTC

(In reply to comment #1)
> Can you point to the spec that says that snprintf shall be undefined when
> -D_XOPEN_SOURCE=500
> 
> I added the strings.h include for strcasecmp

Thanks.
About the specs, my apologies I should have included the references while I had them at hand, and "correctly undefined" sounds a bit blunt. Silly of me.

To correct myself on the subject, what I found while investigating this is that, since snprintf behavior was redefined between standards [1], the headers only define it (and a few others) when the standard the library supports is in use or requested, which is (usually) SUSv2 or ISO C99 or POSIX98 (not 100% sure on the posix one).

While _XOPEN_SOURCE=500 goes back to pre-1998 (speaking of standards) and that (older) implementation of snprintf is not supported on BSD (neither on glibc I think), it's then left undefined (a suggestive way for programs to provide the implementation they want, if I may add).
Linux glibc also behaves in a similar way: one of the requisites for defining snprintf in <stdio.h> is "_XOPEN_SOURCE > 500" (coming from <features.h>). But it's then ||or'ed to another define that comes from _BSD_SOURCE (it sets __USE_BSD), which is a bliss for glibc in this case, given that -D_BSD_SOURCE is also defined by poppler here.

[1] http://www.opengroup.org/onlinepubs/009695399/functions/snprintf.html (at the bottom)

Comment 3 Albert Astals Cid 2010-04-14 11:27:18 UTC

Changed to 600, anyway, that option is only set if you use a non standard compile option that you should not be using unless you know what you are doing.

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