Initializing Redis++ on IDE

[afifzaki]

Hi, thanks for your work.
I try to compile a simple cpp program:

#include <sw/redis++/redis++.h>

using namespace sw::redis;

int main()
{
auto redis = Redis("tcp://127.0.0.1:6379");
return 0;
}

but that script generate an error:

/home/user/Developments/clang/redis_test/main.cpp:10: undefined reference to sw::redis::Redis::Redis(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' CMakeFiles/redis_test.dir/main.cpp.o: In function sw::redis::Connection::ContextDeleter::operator((redisContext*) const':
/usr/local/include/sw/redis++/connection.h:132: undefined reference to `redisFree'

Is there a simplest example do you provide for initiating redisDB?

[sewenew]

Hi @afifzaki

Your code is the simplest way to initializing a connection to Redis.

The problem is that you didn't link hiredis library. redis-plus-plus is a wrapper based on hiredis lib, so you need to install hiredis, and link it.

g++ -std=c++11 -o app app.cpp -lhiredis -lredis++ -pthread

See how to install hiredis for details.

If you still have any problem with redis-plus-plus, feel free to let me know.

Regards

[sewenew]

Hi @afifzaki

I updated the above comment. If you are using GCC, you need to specify -lhiredis and -lredis++ after app.cpp, NOT before it. But if you are using CLANG the order is NOT a problem. I'll update the doc to make it more generic. Thanks for finding the doc bug :)

g++ -std=c++11 -o app app.cpp -lhiredis -lredis++ -pthread

Also, if you link the dynamic libraries, when you running your application, you might get the following error:

error while loading shared libraries: xxx: cannot open shared object file: No such file or directory.

Check this for solution.

Regards

[afifzaki]

Hi,
Thanks for your solution, the code successfully compiles if you're compiling that with your terminal (I'm using ubuntu 18.04). But the problem arose if you try compiling it inside IDE (code block, CLion).

I'm already following every instruction you made (the installation instruction is very clear). Why this is happening?

[sewenew]

Hi @afifzaki

If you're using CLion, you should modify the related CMakeLists.txt file to add hiredis and redis-plus-plus dependencies, and reload it.

The CMakeLists.txt should looks like the following:

cmake_minimum_required(VERSION 3.0.0)

project(app)

set(CMAKE_CXX_FLAGS "-std=c++11 -Wall -W -Werror -fPIC")

set(SOURCE_FILES app.cpp)
add_executable(app ${SOURCE_FILES})

# <------------ add hiredis dependency here --------------->
find_path(HIREDIS_HEADER hiredis)
target_include_directories(app PUBLIC ${HIREDIS_HEADER})

find_library(HIREDIS_LIB hiredis)
target_link_libraries(app ${HIREDIS_LIB})

# <------------ add redis-plus-plus dependency here -------------->
find_path(REDIS_PLUS_PLUS_HEADER sw)      # NOTE: this should be *sw* NOT *redis++*
target_include_directories(app PUBLIC ${REDIS_PLUS_PLUS_HEADER})

find_library(REDIS_PLUS_PLUS_LIB redis++)
target_link_libraries(app ${REDIS_PLUS_PLUS_LIB})

If you installed hiredis and redis-plus-plus at the default location, you can compile it without any other cmake options. However, if you installed these libraries at non-default location, you should also specify the -DCMAKE_PREFIX_PATH cmake option to specify the path where you installed these libraries. See this for how to set cmake option with CLion.

If you're using code block, this might be helpful for how to add dependencies.

Regards

[afifzaki]

Hi,
Thank you very much, the code is perfectly worked in CLion.
I think I won't close this issue because this is very helpful for others who have the same problem.

Good work, keep it up.

[sewenew]

I'm glad that you like redis++. I'll add some instruction on building application with cmake in the documentation.

Thank you again for finding the documentation bug :)

Regards

[yitian108]

hi @sewenew @afifzaki ,
I still encounter this issue, when I write the cmakelists.txt as below, the clion debug report can't find lredis++:

`cmake_minimum_required(VERSION 3.12)
project(redis)

set(CMAKE_CXX_STANDARD 14)

add_executable(${PROJECT_NAME} main.cpp )

find_path(HIREDIS_INC_DIR hiredis)
target_include_directories(${PROJECT_NAME} PUBLIC $ENV{HIREDIS_INC_DIR})

find_library(HIREDIS_LIB_DIR hiredis)
target_link_libraries(${PROJECT_NAME} hiredis)

find_path(REDIS_PLUS_PLUS_INC_DIR sw)
target_include_directories(${PROJECT_NAME} PUBLIC $ENV{REDIS_PLUS_PLUS_INC_DIR})

find_library(REDIS_PLUS_PLUS_LIB_DIR redis++)
target_link_libraries(${PROJECT_NAME} redis++)`

I have troubled with this problem two days, but when I use the command line , it works correctly:

g++ -std=c++11 -I/usr/local/app/redis-plus-plus/include -o redis main.cpp -L/usr/local/app/hiredis/lib -lhiredis -L/usr/local/app/redis-plus-plus/lib -lredis++ -pthread

ps: $ENV{REDIS_PLUS_PLUS_INC_DIR} = /usr/local/app/redis-plus-plus/include
$ENV{REDIS_PLUS_PLUS_LIB_DIR} = /usr/local/app/redis-plus-plus/lib
$ENV{HIREDIS_LIB_DIR} = /usr/local/app/hiredis/lib

Thanks

[sewenew]

@yitian108 Your CMakeLists.txt is incorrect. find_path and find_library will try to find the header and lib path, and save it into the variables you specified. So when you try to call target_include_directories and target_link_libraries, you should use these variables as parameters:

find_path(HIREDIS_INC_DIR hiredis)
target_include_directories(${PROJECT_NAME} PUBLIC ${HIREDIS_INC_DIR})

find_library(HIREDIS_LIB_DIR hiredis)
target_link_libraries(${PROJECT_NAME} ${HIREDIS_LIB_DIR})

find_path(REDIS_PLUS_PLUS_INC_DIR sw)
target_include_directories(${PROJECT_NAME} PUBLIC ${REDIS_PLUS_PLUS_INC_DIR})

find_library(REDIS_PLUS_PLUS_LIB_DIR redis++)
target_link_libraries(${PROJECT_NAME} ${REDIS_PLUS_PLUS_LIB_DIR})

Also, instead of set the environment variable, you should use -DCMAKE_PREFIX_PATH command line arguments to specify the installation path of hiredis and redis++ when running cmake. So that find_path and find_library will correctly find the location and set those variables.

Please check cmake's doc for more details on how to add dependency for a cmake project.

Regards

[yitian108]

Hi @sewenew ,thank you for replying this, I set these environment variables as below, and it real works good in the command line:
$ENV{REDIS_PLUS_PLUS_INC_DIR} = /usr/local/app/redis-plus-plus/include
$ENV{REDIS_PLUS_PLUS_LIB_DIR} = /usr/local/app/redis-plus-plus/lib
$ENV{HIREDIS_LIB_DIR} = /usr/local/app/hiredis/lib

also , I run cmake, I used the options -DCMAKE_PREFIX_PATH -DCMAKE_INSTALL_PREFIX etc, please see below:

cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_PREFIX_PATH=/usr/local/app/hiredis -DCMAKE_INSTALL_PREFIX=/usr/local/app/redis-plus-plus ..

that's I really don't know why it is works good with hiredis and in command line, only does not work with redis++

Regards

[yitian108]

[yitian108]

I use the simple cmakelists.txt as attachment, and message() them in console, the result is the same, can't find the library redis++, I don't know whether it related with the version of clion. I think it should not.