How to compile a static library using the Android NDK?

Question

I'm trying to compile a static library to use on Android but I can't figure out how to compile it. The library uses standard libraries (stdio.h etc...) and libxml2.

I am trying to compile using arm-eabi-gcc but I get the following error:

/cygdrive/c/android-ndk-r4/build/platforms/android-8/arch-x86/usr/include/asm/posix_types.h:15:28: error: posix_types_64.h: No such file or directory

How do I get this to work?

Answer 1

As I understand it, the correct method is to use ndk-build and not invoking the compiler directly.

In Android.mk you need to specify a module for each static library you want to compile, and then specify that your shared library should use it.

Example of a modified Android.mk file of the hello-jni sample project:

LOCAL_PATH := $(call my-dir)

# Define vars for library that will be build statically.
include $(CLEAR_VARS)
LOCAL_MODULE := <module_name>
LOCAL_C_INCLUDES := <header_files_path>
LOCAL_SRC_FILES :=  <list_of_src_files>

# Optional compiler flags.
LOCAL_LDLIBS   = -lz -lm
LOCAL_CFLAGS   = -Wall -pedantic -std=c99 -g

include $(BUILD_STATIC_LIBRARY)

# First lib, which will be built statically.
include $(CLEAR_VARS)
LOCAL_MODULE := hello-jni
LOCAL_STATIC_LIBRARIES := <module_name>
LOCAL_C_INCLUDES := <header_files_path>
LOCAL_SRC_FILES := hello-jni.c

include $(BUILD_SHARED_LIBRARY)

If you want control over which modules to compile when you run ndk-build you can create create a Application.mk file (in the same directory as Android.mk) and list all the modules as in the following example:

APP_MODULES := <module_name_1> <module_name_2> ... <module_name_n>