eRPC C++ Client-Server Matrix Multiply - client and server not communicating

[hale2bopp]

Specs
eRPC Version :
System : MacOS Mojave
Transport used : TCP (with erpc_setup_tcp.cpp used from someone else who updated the same with a pull request)
Message buffer: static
IP address: localhost, Port : 50000
Problem
I have gotten the system to build and am trying to run the client and server on my computer, which means it is ported to unix, and using the TCP transport. I have tried the matrix multiply from the python example and used the same IP address and port and that works, and I can see the packets on wireshark for that port. When I try the same thing for the C++ example, I am not able to do so.

I first built the erpc project so that all the object files were available in Debug/Darwin. I used these to compile the final object files for the server and client. (This is more of a proof of concept which is why I haven't yet written a makefile or a CMake file to compile the project, I want to be sure that it will work before making that effort).

I have attached the IDL files, main.c that I have used. I used erpcgen to generate the shim code for the same, and I am also adding the manual list of compile commands to follow in order to compile the server_main.cpp, client_main.cpp and the final server and client object files.

I am using the same IDL file as the python example, and erpcgen generates the .cpp files required for me with the code to do the matrix multiplication etc. I wrote a main file for the server and client which specifies the transport, message buffer, initializes the server/client, and opens them up for connection.

Code

server_main:
`int main(void){

erpc_transport_t transport = erpc_transport_tcp_init("127.0.0.0", 50000);	

erpc_mbf_t message_buffer_factory = erpc_mbf_static_init();
/* eRPC server side initialization */
erpc_server_init(transport, message_buffer_factory);
printf("eRPC intialized\r\n");
/* adding the service to the server */
erpc_add_service_to_server(create_MatrixMultiplyService_service());
printf("MatrixMultiply service added\r\n");
/* run server */

while(1)
    erpc_server_run();

return 0;

}
`

client_main:

`
int main()
{
/* Matrices definitions */
Matrix matrix1, matrix2, result_matrix = {{1}};

/* init eRPC client environment */
/* TCP transport layer initialization */
erpc_transport_t transport = erpc_transport_tcp_init("127.0.0.0", 50000);	

/* MessageBufferFactory initialization */
erpc_mbf_t message_buffer_factory = erpc_mbf_dynamic_init();   
/* other code like print result matrix */
printf("Initializing client side\n");
/* eRPC client side initialization */
erpc_client_init(transport, message_buffer_factory);
/* other code like init matrix1 and matrix2 values */   
int i,j;

for (i=0;i<matrix_size;i++)
for (j=0;j<matrix_size;j++)
	matrix1[i][j] = 1;

for (i=0;i<matrix_size;i++)
for(j=0;j<matrix_size;j++)
	matrix2[i][j] = 2;

/* other code like print result matrix */
printf("Calling eRPC matrix multiply on server side\n");

while(1){	
/* call eRPC functions */
erpcMatrixMultiply(matrix1, matrix2, result_matrix);

/* other code like print result matrix */
printf("Here is the result of the matrix multiplication: \n");
for (i=0;i<matrix_size;i++){
    for(j=0;j<matrix_size;j++)
            printf("result_matrix[%d][%d] = %d\t",i,j,result_matrix[i][j]);
printf("\n");    
}

}
/* eRPC client side initialization */
erpc_client_deinit();
return 0;

}`

IDL file :

`
program erpc_matrix_multiply

/*! This const defines the matrix size. The value has to be the same as the
Matrix array dimension. Do not forget to re-generate the erpc code once the
matrix size is changed in the erpc file */

const int32 matrix_size = 5;

/*! This is the matrix array type. The dimension has to be the same as the
matrix size const. Do not forget to re-generate the erpc code once the
matrix size is changed in the erpc file */

type Matrix = int32[matrix_size][matrix_size];

interface MatrixMultiplyService {
erpcMatrixMultiply(in Matrix matrix1, in Matrix matrix2, out Matrix result_matrix) -> void
}`

Instructions to build:
`1. make in erpc folder
2. make a folder with the erpc_matrix_multiply.erpc
3. erpcgen on this to generate the shim code in service/erpc_matrix_multiply
After that,

Server-Side commands

1. Step one: make in erpc folder to generate obj files in Debug/Darwin/erpc/obj/erpc_c

2. Compile server.o which is made from erpc_matrix_multiply_server.cpp

Cmd to compile server.o

g++ -I../erpc_c/infra -I../erpc_c/port -I../erpc_c/transports -I../erpc_c/setup -I../erpc_c/config -c service/erpc_matrix_multiply/erpc_matrix_multiply_server.cpp -o server.o -ggdb

3. Compiler server_main.o

Cmd to compile server main

gcc -I../erpc_c/infra -I../erpc_c/port -I../erpc_c/transports -I../erpc_c/setup -I../erpc_c/config -c server_main.c -o server_main.o -ggdb

4. Link both of these into a server executable which actually runs the server

Cmd to compile server all

g++ ../Debug/Darwin/erpc/obj/erpc_c/infra/.o ../Debug/Darwin/erpc/obj/erpc_c/setup/.o ../Debug/Darwin/erpc/obj/erpc_c/port/.o ../Debug/Darwin/erpc/obj/erpc_c/transports/.o server.o server_main.o -o server -ggdb

Client-Side Commands

1. Compile client.o made from erpc_matrix_multiply_client.cpp

g++ -I../erpc_c/infra -I../erpc_c/port -I../erpc_c/transports -I../erpc_c/setup -I../erpc_c/config -c service/erpc_matrix_multiply/erpc_matrix_multiply_client.cpp -o client.o -ggdb

2. Compile client_main.c

Cmd to compile client main

gcc -I../erpc_c/infra -I../erpc_c/port -I../erpc_c/transports -I../erpc_c/setup -I../erpc_c/config -c client_main.c -o client_main.o -ggdb

Cmd to compile client all

g++ ../Debug/Darwin/erpc/obj/erpc_c/infra/.o ../Debug/Darwin/erpc/obj/erpc_c/setup/.o ../Debug/Darwin/erpc/obj/erpc_c/port/.o ../Debug/Darwin/erpc/obj/erpc_c/transports/.o client.o client_main.o -o client -ggdb`

Results
The client and server both appear to 'run' but hang and the client code never goes beyond calling the matrix multiply function on the server. There's no connection between them.
Am I doing something obviously wrong here?

[MichalPrincNXP]

Hi @hale2bopp
the only thing I have noticed when looking into your code is the server_main.cpp: the erpc_server_run() should not be called in the while loop as described in https://github.com/EmbeddedRPC/erpc/wiki/eRPC-infrastructure
It should be like this:

erpc_server_run();
while (1)
    {
    }

I recommend to have a look at https://github.com/EmbeddedRPC/erpc/blob/master/test/common/unit_test_tcp_client.cpp and https://github.com/EmbeddedRPC/erpc/blob/master/test/common/unit_test_tcp_server.cpp sources: these are similar to your case but without using the setup functions.

[hale2bopp]

Issue was - client runs as a server by default, since the boolean which sets it as a client or as a server is set to 1 by default.