Structs starting with 'w' in FreeBSD

• wait4_args kern/kern_exit.c:285
• walkarg net/rtsock.c:498
• wdparams i386/isa/wdreg.h:104
• winsize sys/ioctl.h:44
• write_args kern/sys_generic.c:204
• writev_args kern/sys_generic.c:265