When you link two files that both #include <wchar.h> together you get:
t2.o: In function `wcstoul': /usr/include/wchar.h:540: multiple definition of
`wcstoul'
t1.o:/usr/include/wchar.h:540: first defined here
when you compile with -std=c99.
--
Summary: [4.3] fixincludes needed for wchar from glibc 2.3.6
Product: gcc
Version: 4.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: other
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tbm at cyrius dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31405
