_GLIBCXX_USE_C99 not working?

Dave Korn dave.korn@artimi.com
Fri May 18 11:52:00 GMT 2007

On 17 May 2007 21:32, Christian Franke wrote:

> Defining _GLIBCXX_USE_C99 does not work with current Cygwin C++ includes.
> Testcase:
> #define _GLIBCXX_USE_C99 1 // need std::llabs()

  Can you point me at any documentation that says this is a valid thing to do?
AFAICT that's an internal symbol in the '_' namespace that user code has no
business messing around with.  Cygwin is not a glibc program so telling
libstdc that it is seems inherently bogus to me.

/artimi/software/firmware $ grep -wB1 _GLIBCXX_USE_C99
// Define if C99 features such as lldiv_t, llabs, lldiv should be exposed.
/* #undef _GLIBCXX_USE_C99 */

  As you see, it is part of the internal configuration, generated by autoconf
or some similar process at the time the library is compiled and installed.

"This is an internal header file, included by other library headers. You
should not attempt to use it directly."

  If you want this to work, I guess we shoult implement strtold in newlib, or
patch libstdc for finer granularity in what it assumes _GLIBCXX_USE_C99
implies is available.

Can't think of a witty .sigline today....

Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/

More information about the Cygwin mailing list