On 10/21/2009 04:44 PM, Samuel Thibault wrote: > Pavan Balaji, le Wed 21 Oct 2009 16:40:42 -0500, a écrit : >>> Please read this thread: >>> >>> http://www.open-mpi.org/community/lists/hwloc-devel/2009/09/0054.php >> Thanks. Is the only issue to not use AC_C_RESTRICT that of conflicting >> name space? > > Not only, it's also that you never know in advance which compiler will > be used while including hwloc.h, and thus what _that_ compiler will > support, thus the dynamic discovery.
I'm not sure I understand the problem here. Let me illustrate what I mean. Suppose you are using gcc to compile hwloc and suncc to compile some application using hwloc. Let's say gcc uses __restrict and suncc uses _Restrict (I didn't check what these compilers use; these are just for illustration). hwloc configure.in will have -- AX_PREFIX_CONFIG_H([include/hwloc_config.h], [hwloc]) AC_C_RESTRICT Suppose you compiled hwloc with gcc, you'll get the following in your new config file -- /* Note the hwloc_ prefix added by the AX_PREFIX_CONFIG_H macro */ #define hwloc_restrict __restrict Now, if the application is using suncc, and it tries to find what spelling for restrict it needs to use, it'll come up with -- #define restrict _Restrict These do not conflict at all; hwloc will use its definition of restrict and the application will use its. Why is this a problem? -- Pavan -- Pavan Balaji http://www.mcs.anl.gov/~balaji
