My source code results in this:
// MySQL.cpp : Defines the entry point for the console application.
//
#include <iostream>
#include <winsock.h>
#include <string>
#include <sstream>
#include <stdio.h>
#include <mysql.h>
#define TABLE_OF_INTEREST "some_table"
#define SERVER_NAME "mysql_server"
#define DB_USER "user"
#define DB_USERPASS "pa55w0rd"
#define DB_NAME "db_name"
#define NEWLINE "\n"
using namespace std;
int main()
{
MYSQL *hnd = NULL; // mysql connection handle
const char *sinf = NULL; // mysql server information
if(!mysql_real_connect(hnd, SERVER_NAME, DB_USER, DB_USERPASS, DB_NAME, 0, NULL, 0)
cout << "Something happened.";
return 0;
}
error:
1>------ Build started: Project: MySQL, Configuration: Release Win32 ------
1> MySQL.cpp
1>MySQL.obj : error LNK2001: unresolved external symbol _mysql_real_connect#32
1>c:\users\josiah\documents\visual studio 2010\Projects\MySQL\Release\MySQL.exe : fatal error LNK1120: 1 unresolved external
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
I don't think there issues with the source, I just need help on how to figure out where the problem is.
You're missing a reference to a lib. The C connector should have come with a .lib, add it to the additional input for the linker
Related
I'm working on a STM32MP1 target with yocto. In general I can compile a helloworld .ko file and load it into the kernel. But when I want to compile following:
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/types.h>
static struct platform_device *pdev;
static int __init fake_eth_add(void)
{
int inst_id = 0;
pdev = platform_device_alloc("fake-eth", inst_id);
platform_device_add(pdev);
pr_info("fake-eth added");
return 0;
}
static void __exit fake_eth_put(void)
{
pr_info("fake-fake removed");
platform_device_put(pdev);
}
module_init(fake_eth_add);
module_exit(fake_eth_put);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("John Madieu <john.madieu#gmail.com>");
I get following errors:
ERROR: modpost: "platform_device_put" [/home/rdm/ethtest/eth-ins.ko] undefined!
ERROR: modpost: "platform_device_add" [/home/rdm/ethtest/eth-ins.ko] undefined!
ERROR: modpost: "platform_device_alloc" [/home/rdm/ethtest/eth-ins.ko] undefined!
I check if the platform_device_alloc Symbol/Function is defined and it does:
root#txmp-1570:/lib/modules/5.7.1/source/kernel# grep -w platform_device_alloc /proc/kallsyms
c0547cfc T platform_device_alloc
Now I have learned that the symbols must be in the Module.symvers File tagged as EXPORT_SYMBOL_GPL. The symbols were not there, so I added them to the Module.symvers file:
0x00000000 platform_device_alloc vmlinux EXPORT_SYMBOL_GPL
0x00000000 platform_device_add vmlinux EXPORT_SYMBOL_GPL
0x00000000 platform_device_put vmlinux EXPORT_SYMBOL_GPL
Now the code compiles! But when I want to load it with insmod, then I get following error:
root#txmp-1570:/home/rdm/ethtest# insmod eth-ins.ko
insmod: ERROR: could not insert module eth-ins.ko: Unknown symbol in module
And the dmseg logs:
[ 2954.658383] eth_ins: Unknown symbol platform_device_put (err -2)
[ 2954.664194] eth_ins: Unknown symbol platform_device_add (err -2)
[ 2954.672737] eth_ins: Unknown symbol platform_device_alloc (err -2)
What am I missing? Why did I have to append the Module.symvers file by myself? Did I miss something regarding setting up the enviromnent for kernel driver development?
The complete error output:
SDL2main.lib(SDL_windows_main.obj) : error LNK2019: unresolved external symbol __imp_CommandLineToArgvW referenced in function main_getcmdline
My compiler options:
cl -D WINDOWS -nologo -W4 -WX -wd4100 -Fe"output_file.exe" input_file.c SDL2.lib SDL2main.lib -I ./SDL2-2.0.12/include -link -LIBPATH:./SDL2-2.0.12/lib/x64 -SUBSYSTEM:CONSOLE
My input_file.c header and main function:
#ifdef LINUX
#include <SDL2/SDL.h> /* Comes with stdio.h and stdlib.h */
#elif WINDOWS
#include <stdio.h>
#include "SDL.h"
#endif
int main(int argc, char* argv[]) {
if(SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO|SDL_INIT_TIMER) != 0)
{
fprintf(stderr, "Failed to initialize SDL: %s\n", SDL_GetError());
return -1;
}
. . .
The SDL development folder used in the command line arguments is the development libraries zip file downloaded from libsdl.org
Why am I getting this error?
you also need to use the library called "shell32.lib"
cl -D WINDOWS -nologo -W4 -WX -wd4100 -Fe"output_file.exe" input_file.c shell32.lib SDL2.lib SDL2main.lib -I ./SDL2-2.0.12/include -link -LIBPATH:./SDL2-2.0.12/lib/x64 -SUBSYSTEM:CONSOLE
I'm trying to run some software inside a docker container, which wants to do VT_SETMODE for the tty currently in use. This will always fail with an error saying "Operation not permitted".
I've tried playing around with permissions/groups with no luck.
Finally I created a small snippet to reproduce the error:
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <linux/vt.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
int main() {
const char *tty_path;
tty_path = "/dev/tty1";
int fd = open(tty_path, O_RDWR | O_CLOEXEC);
if (fd < 0) {
printf("ERROR: Failed to open %s\n", strerror(errno));
return 1;
}
struct vt_mode mode = {
.mode = VT_AUTO,
};
errno = 0;
ioctl(fd, VT_SETMODE, &mode);
if (errno) {
printf("ERROR: %s\n", strerror(errno));
return 1;
}
return 0;
}
I ran the code inside a docker container with a simple dockerfile:
FROM archlinux/base
RUN pacman -Sy --noconfirm gcc
That was started with command:
docker build -f Dockerfile -t tty-test . && docker run --device /dev/tty1 -v $HOME/tty-test:/volume -it tty-test /bin/bash -c 'cd /volume && gcc tty_r.c && ./a.out ; /bin/bash'
Output is this:
ERROR: Operation not permitted
Can anyone explain why the tty is not accessible from the container, or is there some way to give more control to the container?
Okay it seems that I have solved my own problem. I was trying to run the code inside a container which had no privilege to do tty-configuration. Adding --cap-add SYS_TTY_CONFIG to the docker run command fixed the issue.
Trying to build pjSIP from sources for Android, using following guide - https://trac.pjsip.org/repos/wiki/Getting-Started/Android
Checkout sources of pjsip (2.5)
export ANDROID_NDK_ROOT=/home/dev/android/android-ndk-r9b
export TARGET_ABI=armeabi
export APP_PLATFORM=android-13
./configure-android --use-ndk-cflags --disable-video --disable-l16-codec --disable-gsm-codec --disable-g722-codec --disable-g7221-codec --disable-ssl --disable-ilbc-codec --disable-tls
configuration is completed successfully.
make dep && make clean && make
And I got following error - >
../src/pj/guid_android.c:43: error: undefined reference to 'pj_jni_jvm'
../src/pj/guid_android.c:117: error: undefined reference to 'pj_jni_jvm'
The command invoked by linked which leads to this error
/home/dev/android/android-ndk-r9b/toolchains/arm-linux-androideabi-4.8/prebuilt/linux-x86/bin/arm-linux-androideabi-gcc -o ../bin/pjlib-test-arm-unknown-linux-androideabi \
output/pjlib-test-arm-unknown-linux-androideabi/main.o output/pjlib-test-arm-unknown-linux-androideabi/activesock.o output/pjlib-test-arm-unknown-linux-androideabi/atomic.o output/pjlib-test-arm-unknown-linux-androideabi/echo_clt.o output/pjlib-test-arm-unknown-linux-androideabi/errno.o output/pjlib-test-arm-unknown-linux-androideabi/exception.o output/pjlib-test-arm-unknown-linux-androideabi/fifobuf.o output/pjlib-test-arm-unknown-linux-androideabi/file.o output/pjlib-test-arm-unknown-linux-androideabi/hash_test.o output/pjlib-test-arm-unknown-linux-androideabi/ioq_perf.o output/pjlib-test-arm-unknown-linux-androideabi/ioq_udp.o output/pjlib-test-arm-unknown-linux-androideabi/ioq_unreg.o output/pjlib-test-arm-unknown-linux-androideabi/ioq_tcp.o output/pjlib-test-arm-unknown-linux-androideabi/list.o output/pjlib-test-arm-unknown-linux-androideabi/mutex.o output/pjlib-test-arm-unknown-linux-androideabi/os.o output/pjlib-test-arm-unknown-linux-androideabi/pool.o output/pjlib-test-arm-unknown-linux-androideabi/pool_perf.o output/pjlib-test-arm-unknown-linux-androideabi/rand.o output/pjlib-test-arm-unknown-linux-androideabi/rbtree.o output/pjlib-test-arm-unknown-linux-androideabi/select.o output/pjlib-test-arm-unknown-linux-androideabi/sleep.o output/pjlib-test-arm-unknown-linux-androideabi/sock.o output/pjlib-test-arm-unknown-linux-androideabi/sock_perf.o output/pjlib-test-arm-unknown-linux-androideabi/ssl_sock.o output/pjlib-test-arm-unknown-linux-androideabi/string.o output/pjlib-test-arm-unknown-linux-androideabi/test.o output/pjlib-test-arm-unknown-linux-androideabi/thread.o output/pjlib-test-arm-unknown-linux-androideabi/timer.o output/pjlib-test-arm-unknown-linux-androideabi/timestamp.o output/pjlib-test-arm-unknown-linux-androideabi/udp_echo_srv_sync.o output/pjlib-test-arm-unknown-linux-androideabi/udp_echo_srv_ioqueue.o output/pjlib-test-arm-unknown-linux-androideabi/util.o -lpj-arm-unknown-linux-androideabi -nostdlib -L/home/dev/android/android-ndk-r9b/platforms/android-13/arch-arm/usr/lib -L/home/dev/android/android-ndk-r9b/sources/cxx-stl/gnu-libstdc++/4.8/libs/armeabi/ -lm /home/dev/android/android-ndk-r9b/platforms/android-13/arch-arm/usr/lib/crtbegin_so.o -lgnustl_static -lc -lgcc -ldl -lOpenSLES -llog -L/home/dev/android/pjproject-2.5/pjlib/lib -L/home/dev/android/pjproject-2.5/pjlib-util/lib -L/home/dev/android/pjproject-2.5/pjnath/lib -L/home/dev/android/pjproject-2.5/pjmedia/lib -L/home/dev/android/pjproject-2.5/pjsip/lib -L/home/dev/android/pjproject-2.5/third_party/lib -nostdlib -L/home/dev/android/android-ndk-r9b/platforms/android-13/arch-arm/usr/lib -L/home/dev/android/android-ndk-r9b/sources/cxx-stl/gnu-libstdc++/4.8/libs/armeabi/
Code of guid_androind.c
#include <pj/guid.h>
#include <pj/log.h>
#include <pj/string.h>
#include <jni.h>
extern JavaVM *pj_jni_jvm;
static pj_bool_t attach_jvm(JNIEnv **jni_env)
{
if ((*pj_jni_jvm)->GetEnv(pj_jni_jvm, (void **)jni_env,
JNI_VERSION_1_4) < 0)
{
if ((*pj_jni_jvm)->AttachCurrentThread(pj_jni_jvm, jni_env, NULL) < 0)
{
jni_env = NULL;
return PJ_FALSE;
}
return PJ_TRUE;
}
return PJ_FALSE;
}
#define detach_jvm(attached) \
if (attached) \
(*pj_jni_jvm)->DetachCurrentThread(pj_jni_jvm);
Struggling with this error for whole day, any clue is highly appreciated. Meanwhile I'm able to build version 2.3 without any errors, but not 2.5
I believe you missed a step.
https://trac.pjsip.org/repos/wiki/Getting-Started/Android#BuildPreparation
Set your config_site.h to the following:
/* Activate Android specific settings in the 'config_site_sample.h' */
#define PJ_CONFIG_ANDROID 1
#include <pj/config_site_sample.h>
I am trying to debug a JNI C function by inserting log messages, but I can't get it to work. To start with I am just trying to modify the hello-jni example that comes with Android Studio. This is the modified code:
#include <string.h>
#include <jni.h>
#include <android/log.h>
jstring
Java_com_example_hellojni_HelloJni_stringFromJNI( JNIEnv* env,
jobject thiz )
{
#if defined(__arm__)
#if defined(__ARM_ARCH_7A__)
#if defined(__ARM_NEON__)
#if defined(__ARM_PCS_VFP)
#define ABI "armeabi-v7a/NEON (hard-float)"
#else
#define ABI "armeabi-v7a/NEON"
#endif
#else
#if defined(__ARM_PCS_VFP)
#define ABI "armeabi-v7a (hard-float)"
#else
#define ABI "armeabi-v7a"
#endif
#endif
#else
#define ABI "armeabi"
#endif
#elif defined(__i386__)
#define ABI "x86"
#elif defined(__x86_64__)
#define ABI "x86_64"
#elif defined(__mips64) /* mips64el-* toolchain defines __mips__ too */
#define ABI "mips64"
#elif defined(__mips__)
#define ABI "mips"
#elif defined(__aarch64__)
#define ABI "arm64-v8a"
#else
#define ABI "unknown"
#endif
__android_log_write(ANDROID_LOG_ERROR, "TEST_TAG", "Error here");
return (*env)->NewStringUTF(env, "Hello from JNI ! Compiled with ABI " ABI ".");
}
And this is my Android.mk file:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := hello-jni
LOCAL_SRC_FILES := hello-jni.c
LOCAL_LDFLAGS := -llog
include $(BUILD_SHARED_LIBRARY)
When I use the ndk-build script the libhello-jni.so files get built no problem. When I try to build the project in Android Studio I get the following gradle error message
Information:Gradle tasks [:app:assembleDebug]
:app:preBuild
:app:compileDebugNdk
C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\obj/local/arm64-v8a/objs/hello-jni/C_\Android\projects\hello-jni\app\src\main\jni\hello-jni.o: In function `Java_com_example_hellojni_HelloJni_stringFromJNI':
hello-jni.c:(.text.Java_com_example_hellojni_HelloJni_stringFromJNI+0x24): undefined reference to `__android_log_write'
Error:error: ld returned 1 exit status
make.exe: *** [C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\obj/local/arm64-v8a/libhello-jni.so] Error 1
Error:Execution failed for task ':app:compileDebugNdk'.
> com.android.ide.common.internal.LoggedErrorException: Failed to run command:
C:\Android\android-ndk-r10c\ndk-build.cmd NDK_PROJECT_PATH=null APP_BUILD_SCRIPT=C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\Android.mk APP_PLATFORM=android-19 NDK_OUT=C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\obj NDK_LIBS_OUT=C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\lib APP_ABI=all
Error Code:
2
Output:
C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\obj/local/arm64-v8a/objs/hello-jni/C_\Android\projects\hello-jni\app\src\main\jni\hello-jni.o: In function `Java_com_example_hellojni_HelloJni_stringFromJNI':
hello-jni.c:(.text.Java_com_example_hellojni_HelloJni_stringFromJNI+0x24): undefined reference to `__android_log_write'
collect2.exe: error: ld returned 1 exit status
make.exe: *** [C:\Android\projects\hello-jni\app\build\intermediates\ndk\debug\obj/local/arm64-v8a/libhello-jni.so] Error 1
Information:BUILD FAILED
Information:Total time: 3.297 secs
Information:2 errors
Information:0 warnings
Information:See complete output in console
I've tried the suggestions given in this question, but I still get the same error: What is the Log API to call from an Android JNI program?
What am I doing wrong?
I'm using Android Studio 0.8.9 and NDK r10c.
I found an answer after a bit more searching.
If I build the .so files using the ndk-build script on the command line and add
sourceSets.main {
jni.srcDirs = []
jniLibs.srcDir 'src/main/libs'
}
into my build.gradle file so gradle doesn't try to build the .so files it all then works. Looks like a problem with Android Studio-Gradle-NDK integration?
I found the answer here https://stackoverflow.com/a/21111458/4182796
Ugly workaround is to remove function call and rebuild sources just add this after includes :
#if 1
#undef __android_log_print
#define __android_log_print(...) {}
#endif