suggested patches for C/C++ math library macros

I have been volunteering to do maintenance on the blitz C++ Array class library for the past few years. As you know, several of the C++ support macros were contributed by the author of blitz, Todd Veldhuizen. I have run across a few minor bugs and inconsistencies with the m4 macros that check for some specific math routines. I am attaching a couple of patch files that correct these problems.

The ieee_math and system_v_math macros refer to fairly obscure math library standards. As near as I can tell from flipping through math.h header files on various systems, "ieee" corresponds to items provided when XOPEN_SOURCE or the equivalent macro is defined. The SGI math.h header refers to these items as the XPG4 standard. Meanwhile, "system_v" appears to correspond to items provided in the C99 extensions to the C standard library. Based upon the categorizations that appear in current math.h header files, I have supplemented and reorganized the lists of functions that are tested for in the ieee_math and system_v_math macros. I have added tests for cbrt, jn, gamma and yn to ieee_math. I have moved tests for ilogb, hypot, nextafter, remainder and scalb from system_v_math to ieee_math. In addition, I added tests for trunc and finite to system_v_math, and I removed the test for fmod because it is in the standard C math library.

I also corrected a problem that was causing the ieee_math check to possibly fail under the IBM xlC compiler. If you compile with the -qthreaded flag or use the reentrant version xlC_r of the compiler, the IBM math.h header provides reentrant versions of the gamma and lgamma functions. So I have modified the test program in the ieee_math macro to account for this possibility and allow the ieee_math check to pass under xlC_r.

From:	Julian C. Cummings
Subject:	suggested patches for C/C++ math library macros
Date:	Tue, 3 Aug 2004 12:29:55 -0700