HowToAddStaticLibrary.md

How to add Static Library

There are two methods to include static library, adding it into arch library and adding it as a new library.

Adding it into arch library

Makefile or Make.defs in arch can include it for architecture specific library as mentioned below.
Libarch.a includes new static library inside.

VPATH += <LIB_PATH>
EXTRA_LIBS += <LIB_PATH>/<LIB_NAME>.a

The LIB_PATH should be a relative path from os/arch/arm/src.

For example,

VPATH += chip/abc
EXTRA_LIBS += chip/abc/libnew.a

This change makes it add to Tizen RT binary by Makefile which is at os/arch/arm/src folder.

$(BIN_DIR)/tinyara$(EXEEXT): $(HEAD_OBJ) board/libboard$(LIBEXT)
	$(Q) echo "LD: tinyara"
	$(Q) $(LD) --entry=__start $(LDFLAGS) $(LIBPATHS) $(EXTRA_LIBPATHS) \
		-o $(TINYARA) $(HEAD_OBJ) $(EXTRA_OBJS) \
		--start-group $(LDLIBS) $(EXTRA_LIBS) $(LIBGCC) --end-group -Map $(TOPDIR)/../build/output/bin/tinyara.map

Adding it as a new library

Tizen RT includes it as separated library, not merge it to existed library.

1. Add it in Libtargets.mk.

   $(LIBRARIES_DIR)$(DELIM)<LIB_NAME>$(LIBEXT): <LIB_PATH>$(DELIM)<LIB_NAME>$(LIBEXT)
   	$(Q) install <LIB_PATH>$(DELIM)<LIB_NAME>$(LIBEXT) $(LIBRARIES_DIR)$(DELIM)<LIB_NAME>$(LIBEXT)
   

2. Add it in FlatLibs.mk, ProtectedLibs.mk and KernelLibs.mk.

   For kernel library,

   TINYARALIBS += $(LIBRARIES_DIR)$(DELIM)<LIB_NAME>$(LIBEXT)
   

   For user library,

   USERLIBS += $(LIBRARIES_DIR)$(DELIM)<LIB_NAME>$(LIBEXT)
   

   In flat build, there is no difference between TINYARALIBS and USERLIBS.
   But in protected build and kernel build, Tizen RT splits kernel space and user space. So, new static library should be included at appropriate space.

The LIB_PATH should be a relative path from os.