CODEWITHSUNDEEP
android-ndk
Andreas
Andreas

Reputation: 10037

How to detect armeabi and armeabi-v7a from C code

I'm building a fat APK that contains separate *.so libs for armeabi and armeabi-v7a. I build using the command line only (i.e. using ndk-build and ant). Is there a way to detect from my C code whether the ndk-buildis currently building for armeabi or for armeabi-v7a? Preferably, I would like to be able to detect this at compile time, but if there is no other choice an architecture detection at runtime would also be sufficient.

E.g. is there something like

#ifdef __armeabiv7a__
...
#else
...
#endif

to detect the architecture at compile time?

I know that I can pass additional compiler flags in LOCAL_CFLAGSin Android.mk but these flags are always passed for all architectures so it doesn't help me. Or is there a tag that I could use in Android.mk to pass specific flags for armeabi or armeabi-v7aonly?

Upvotes: 1

Views: 827

Answers (2)

mstorsjo
mstorsjo

Reputation: 13317

At least gcc provides quite a bit of predefined macros that one can check, to get info about the current ABI. For this case, you could check either this:

#if defined(__ARM_ARCH) && __ARM_ARCH >= 7

Or this:

#ifdef __ARM_ARCH_7A__

By manually setting these in the makefile as suggested by Michael you don't need to keep track of what different ABI macros there are, though, and have less risk of getting into unintended situations if moving to a compiler that doesn't have the same predefined macros (such as the MSVC compiler, although you won't be using that for Android).

Upvotes: 1

Michael
Michael

Reputation: 58427

I know that I can pass additional compiler flags in LOCAL_CFLAGS in Android.mk but these flags are always passed for all architectures

There's nothing preventing you from setting a flag only when building for a certain ABI:

ifeq ($(TARGET_ARCH_ABI),armeabi-v7a)
    LOCAL_CFLAGS += -DARMEABI_V7A
endif

Upvotes: 2

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