[apple/xnu.git] / libkern / kmod / README

#
# Subtle combination of files and libraries make up the C++ runtime system for
# kernel modules.  We are dependant on the KernelModule kmod.make and
# CreateKModInfo.perl scripts to be exactly instep with both this library
# module and the libkmod module as well.
#
# If you do any maintenance on any of the following files make sure great
# care is taken to keep them in Sync.
#    extenTools/KernelModule.bproj/kmod.make
#    extenTools/KernelModule.bproj/CreateKModInfo.perl
#    IOKitUser/kmodc++/pure.c
#    IOKitUser/kmodc++/cplus_start.c
#    IOKitUser/kmodc++/cplus_start.c
#    IOKitUser/kmodc/c_start.c
#    IOKitUser/kmodc/c_stop.c
#
# The trick is that the linkline links all of the developers modules.
# If any static constructors are used .constructors_used will be left as
# an undefined symbol.  This symbol is exported by the cplus_start.c routine
# which automatically brings in the appropriate C++ _start routine.  However
# the actual _start symbol is only required by the kmod_info structure that
# is created and initialized by the CreateKModInfo.perl script.  If no C++
# was used the _start will be an undefined symbol that is finally satisfied
# by the c_start module in the kmod library.
# 
# The linkline must look like this.
#    *.o -lkmodc++ kmod_info.o -lkmod
#
Commit	Line	Data
1c79356b A	1	#
	2	# Subtle combination of files and libraries make up the C++ runtime system for
	3	# kernel modules. We are dependant on the KernelModule kmod.make and
	4	# CreateKModInfo.perl scripts to be exactly instep with both this library
	5	# module and the libkmod module as well.
	6	#
	7	# If you do any maintenance on any of the following files make sure great
	8	# care is taken to keep them in Sync.
	9	# extenTools/KernelModule.bproj/kmod.make
	10	# extenTools/KernelModule.bproj/CreateKModInfo.perl
	11	# IOKitUser/kmodc++/pure.c
	12	# IOKitUser/kmodc++/cplus_start.c
	13	# IOKitUser/kmodc++/cplus_start.c
	14	# IOKitUser/kmodc/c_start.c
	15	# IOKitUser/kmodc/c_stop.c
	16	#
	17	# The trick is that the linkline links all of the developers modules.
	18	# If any static constructors are used .constructors_used will be left as
	19	# an undefined symbol. This symbol is exported by the cplus_start.c routine
	20	# which automatically brings in the appropriate C++ _start routine. However
	21	# the actual _start symbol is only required by the kmod_info structure that
	22	# is created and initialized by the CreateKModInfo.perl script. If no C++
	23	# was used the _start will be an undefined symbol that is finally satisfied
	24	# by the c_start module in the kmod library.
	25	#
	26	# The linkline must look like this.
	27	# *.o -lkmodc++ kmod_info.o -lkmod
	28	#