CODEWITHSUNDEEP
androidandroid-ndkandroid-studiognubuild.gradle
Brian S
Brian S

Reputation: 3234

Using thread and mutex in Android Studio with ndk 10c

I have the latest version of the 64bit NDK (r10c), and the latest version of Android Studio I can download (0.8.14).

I am making a number of JNI calls to use String, Vector, Atomic, etc. But I can not figure out how to use thread and mutex.

Both of them give me the same error 

Error:(92, 5) error: 'thread' is not a member of 'std'
Error:(93, 5) error: 'mutex' is not a member of 'std'

I'm sure that the NDK is using 4.9 of the gnu-libstdc++. If I put in a #error in the file I see my error and compilation stops. It appears that I'm not missing any defines since I can put the #error inside the class and see it.

Here is the ndk config in my build.gradle

ndk {
    moduleName "myLib"
    ldLibs "log"
    stl "gnustl_shared"
    cFlags "-std=c++11 -frtti -fexceptions -pthread"
}

The -frtti and -pthread seem to make no difference. I have also tried stl of gnustl_shared as well as gnustl_static, no difference.

Upvotes: 1

Views: 2576

Answers (1)

Alex Cohn
Alex Cohn

Reputation: 57163

By default, NDK still uses GCC 4.6 which has crippled support for C++11. You need the grade equivalent for setting NDK_TOOLCHAIN_VERSION:=4.9 in Application.mk. You can find some answers here: how to specify NDK_TOOLCHAIN_VERSION in gradle file for android ndk build, but unfortunately the bottom line is that today you have to disable automatic ndk-build call by setting jni.srcDirs to empty and use the Android.mk and Application.mk files the old way.

So, if in your jni directory, there are files file1.cpp and file2.cpp, you will need the following Android.mk

LOCAL_PATH            := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE          := myLib
LOCAL_SRC_FILES       := file1.cpp file2.cpp
LOCAL_LDLIBS          := -llog
LOCAL_CFLAGS          := -std=c++11 -frtti -fexceptions -pthread

... and Application.mk

APP_ABI               := armeabi-v7a
APP_STL               := gnustl_shared
NDK_TOOLCHAIN_VERSION := 4.9

Upvotes: 3

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