#1754: _BSD_SOURCE in glibc apparently going away ------------------------+--------------------------------------------------- Reporter: rhaas | Owner: Type: task | Status: new Priority: unset | Milestone: Component: SimFactory | Version: development version Keywords: | ------------------------+--------------------------------------------------- I just stumbled accross https://lwn.net/Articles/634207/ which states:
--8<-- Also in 2.20, the _BSD_SOURCE and _SVID_SOURCE feature test macros have been removed. The declarations formerly available under those macros are now under _DEFAULT_SOURCE, but, since it's the default, one need not set it explicitly. Roland's suggestion, though, was that most code would (continue to) want to use _GNU_SOURCE or one of the POSIX-specific macros. (See this article for an introduction to glibc feature test macros). --8<--
We use this in some of our option lists to make {{{M_PI}}} and {{{strdup}}} visible.
#1754: _BSD_SOURCE in glibc apparently going away -------------------------+-------------------------------------------------- Reporter: rhaas | Owner: Type: task | Status: new Priority: unset | Milestone: Component: SimFactory | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by rhaas):
For alternative options see #1712 which suggests {{{_XOPEN_SOURCE}}} and {{{_XOPEN_SOURCE_EXTENDED}}}.
#1754: _BSD_SOURCE in glibc apparently going away -------------------------+-------------------------------------------------- Reporter: rhaas | Owner: Type: task | Status: new Priority: unset | Milestone: Component: SimFactory | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by knarf):
Replying to [ticket:1754 rhaas]:
I just stumbled accross https://lwn.net/Articles/634207/ which states:
--8<-- Also in 2.20, the _BSD_SOURCE and _SVID_SOURCE feature test macros have
been removed. The declarations formerly available under those macros are now under _DEFAULT_SOURCE, but, since it's the default, one need not set it explicitly. Roland's suggestion, though, was that most code would (continue to) want to use _GNU_SOURCE or one of the POSIX-specific macros. (See this article for an introduction to glibc feature test macros).
--8<--
Worth mentioning (should be obvious due to the quote, but wasn't for me), that this "Roland" isn't "our" Roland. :)
So, in order for us to support all glibc versions, should we define _BSD_SOURCE _and_ _DEFAULT_SOURCE?
Frank
#1754: _BSD_SOURCE in glibc apparently going away -------------------------+-------------------------------------------------- Reporter: rhaas | Owner: Type: task | Status: new Priority: unset | Milestone: Component: SimFactory | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by rhaas):
Yes the "Roland" in the quote is not me.
We'd have to check. It is not clear to me what happens if one defines both say _DEFAULT_SOURCE and _POSIX_SOURCE, it may depend on how exactly things appear in feature.h. We may not have to do anything other than setting _BSD_SOURCE which will work for old glibc and new glibc will give us {{{M_PI}}} independent of whether or not {{{_BSD_SOURCE}}} is set (though maybe {{{__STRICT_ANSI__}}} may cause issues). The help text spit out by configure when it finds that {{{M_PI}}} is not defined now says to use _XOPEN_SOURCE, since the actual definition of {{{M_PI}}} directly depends on {{{__USE_BSD}}} and {{{__USE_XOPEN}}} though that may be changed to something else of course. I'd say we leave things as they are for now until we actually encounter a system that has issues.
#1754: _BSD_SOURCE in glibc apparently going away -------------------------+-------------------------------------------------- Reporter: rhaas | Owner: Type: task | Status: new Priority: unset | Milestone: Component: SimFactory | Version: development version Resolution: | Keywords: -------------------------+--------------------------------------------------
Comment (by knarf):
Just defining _BSD_SOURCE I think will trigger a warning, unless _DEFAULT_SOURCE isn't defined as well. https://lwn.net/Articles/590381/ : {{{ The first of these patches converts _BSD_SOURCE and _SVID_SOURCE into synonyms for _DEFAULT_SOURCE. The deprecated macros remain effective, but cause compile-time warnings to be generated if they are used (unless _DEFAULT_SOURCE is also defined). }}}
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