Error when connecting Raspberry PI to MATLAB: "json-c/json.h: No such file or directory"

Hi,

2 months ago I connected Raspberry Pi to Matlab and it worked.

Now, I'm trying to connect other raspberry pi to Matlab and I get the error below... please, someone can help me to solve it??

All the explanations that I have find in answers to questions here is not working for me...

>> b=raspi('...','...','...')
### Updating Raspberry Pi I/O server...
### Connecting to board...
### Connected to 192.168.62.16...
### Creating server folder...
### Transferring source files...
### Building MATLAB I/O server...
Error executing command "make ONLY_MATLAB_IO=0 -C /opt/MATLAB/mw_server_v20.2.0 -f Makefile". Details:

STDERR: IO_wrapperv4l2.c: In function ‘v4l2CameraInitialize’:
IO_wrapperv4l2.c:43:9: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
         printf("Webcam: Initialized successfully \n");
         ^~~~~~
IO_wrapperv4l2.c:43:9: warning: incompatible implicit declaration of built-in function ‘printf’
IO_wrapperv4l2.c:43:9: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
IO_wrapperv4l2.c:11:1:
+#include <stdio.h>

IO_wrapperv4l2.c:43:9:
         printf("Webcam: Initialized successfully \n");
         ^~~~~~
IO_wrapperv4l2.c:45:9: warning: incompatible implicit declaration of built-in function ‘printf’
         printf("Webcam: Initialization failed \n");
         ^~~~~~
IO_wrapperv4l2.c:45:9: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
IO_wrapperv4l2.c: In function ‘v4l2CameraSnapshot’:
IO_wrapperv4l2.c:96:5: warning: incompatible implicit declaration of built-in function ‘printf’
     printf("Webcam: Sent an image of framesize %u \n",payloadSize);
     ^~~~~~
IO_wrapperv4l2.c:96:5: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
v4l2_cam.c: In function ‘EXT_webcamInit’:
v4l2_cam.c:900:26: warning: unused variable ‘imageHeight’ [-Wunused-variable]
     uint32_T imageWidth, imageHeight;
                          ^~~~~~~~~~~
v4l2_cam.c:900:14: warning: unused variable ‘imageWidth’ [-Wunused-variable]
     uint32_T imageWidth, imageHeight;
              ^~~~~~~~~~
v4l2_cam.c:898:9: warning: unused variable ‘ret’ [-Wunused-variable]
     int ret = 0;
         ^~~
In file included from v4l2_cam.c:21:
At top level:
availableWebcam.h:29:36: warning: ‘numSupportedRes’ defined but not used [-Wunused-variable]
 static int numberOfConnetions = 0, numSupportedRes[10];
                                    ^~~~~~~~~~~~~~~
availableWebcam.h:29:12: warning: ‘numberOfConnetions’ defined but not used [-Wunused-variable]
 static int numberOfConnetions = 0, numSupportedRes[10];
            ^~~~~~~~~~~~~~~~~~
IO_wrapperCameraboard.c: In function ‘camerboardInitialize’:
IO_wrapperCameraboard.c:38:19: warning: pointer targets in assignment from ‘uint8_T *’ {aka ‘unsigned char *’} to ‘char_T *’ {aka ‘char *’} differ in
signedness [-Wpointer-sign]
     controlParams = &payloadBufferRx[index];
                   ^
IO_wrapperCameraboard.c:41:5: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
     printf("REQUEST_CAMERABOARD_INIT: (w, h, fps, q) = [%d, %d, %d, %d]\n", width, height,
     ^~~~~~
IO_wrapperCameraboard.c:41:5: warning: incompatible implicit declaration of built-in function ‘printf’
IO_wrapperCameraboard.c:41:5: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
IO_wrapperCameraboard.c:11:1:
+#include <stdio.h>

IO_wrapperCameraboard.c:41:5:
     printf("REQUEST_CAMERABOARD_INIT: (w, h, fps, q) = [%d, %d, %d, %d]\n", width, height,
     ^~~~~~
IO_wrapperCameraboard.c: In function ‘cameraboardSnapshot’:
IO_wrapperCameraboard.c:66:5: warning: incompatible implicit declaration of built-in function ‘printf’
     printf("REQUEST_CAMERABOARD_SNAPSHOT \n");
     ^~~~~~
IO_wrapperCameraboard.c:66:5: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
IO_wrapperCameraboard.c: In function ‘cameraboardControl’:
IO_wrapperCameraboard.c:95:19: warning: pointer targets in assignment from ‘uint8_T *’ {aka ‘unsigned char *’} to ‘char_T *’ {aka ‘char *’} differ in
signedness [-Wpointer-sign]
     controlParams = &payloadBufferRx[0];
                   ^
IO_wrapperCameraboard.c:96:5: warning: incompatible implicit declaration of built-in function ‘printf’
     printf("REQUEST_CAMERABOARD_CONTROL: %s \n", controlParams);
     ^~~~~~
IO_wrapperCameraboard.c:96:5: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
IO_wrapperCameraboard.c: In function ‘cameraboardTerminate’:
IO_wrapperCameraboard.c:118:5: warning: incompatible implicit declaration of built-in function ‘printf’
     printf("REQUEST_CAMERABOARD_TERMINATE \n");
     ^~~~~~
IO_wrapperCameraboard.c:118:5: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’
availableWebcam.c: In function ‘getCameraResolution’:
availableWebcam.c:156:11: warning: unused variable ‘search’ [-Wunused-variable]
     char *search = "x";
           ^~~~~~
availableWebcam.c:155:11: warning: unused variable ‘token’ [-Wunused-variable]
     char *token;
           ^~~~~
availableWebcam.c:153:16: warning: unused variable ‘indx_count’ [-Wunused-variable]
     static int indx_count = 0;
                ^~~~~~~~~~
availableWebcam.c: In function ‘getCameraAddrIndex’:
availableWebcam.c:145:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
availableWebcam.c: In function ‘validateResolution’:
availableWebcam.c:226:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
At top level:
availableWebcam.c:153:16: warning: ‘indx_count’ defined but not used [-Wunused-variable]
     static int indx_count = 0;
                ^~~~~~~~~~
picam.c: In function ‘EXT_CAMERABOARD_init’:
picam.c:515:9: warning: unused variable ‘result’ [-Wunused-variable]
     int result = EXT_CAMERABOARD_terminate();
         ^~~~~~
IO_wrapperLED.c: In function ‘setLEDTrigger’:
IO_wrapperLED.c:54:13: warning: pointer targets in assignment from ‘uint8_T *’ {aka ‘unsigned char *’} to ‘char_T *’ {aka ‘char *’} differ in signedness
[-Wpointer-sign]
     trigger = &payloadBufferRx[index];
             ^
MW_I2C.c: In function ‘I2C_open’:
MW_I2C.c:41:19: warning: unused variable ‘i2c_funcs’ [-Wunused-variable]
     unsigned long i2c_funcs = 0;
                   ^~~~~~~~~
MW_I2C.c: In function ‘EXT_I2C_writeH’:
MW_I2C.c:75:17: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
         msg.buf = data;
                 ^
MW_I2C.c: In function ‘MW_I2C_MasterWrite’:
MW_I2C.c:196:9: warning: unused variable ‘i’ [-Wunused-variable]
     int i;
         ^
In file included from IO_wrapperNanomsgPubSub.h:16,
                 from customFunction.c:21:
MW_JSONParser.h:8:10: fatal error: json-c/json.h: No such file or directory
 #include <json-c/json.h>
          ^~~~~~~~~~~~~~~
compilation terminated.
make: *** [Makefile:81: obj/customFunction.o] Error 1

STDOUT: make: Entering directory '/opt/MATLAB/mw_server_v20.2.0'
[Compiling] GPIO.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE GPIO.c -o obj/GPIO.o
[Compiling] IO_wrapperv4l2.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE IO_wrapperv4l2.c -o obj/IO_wrapperv4l2.o
[Compiling] MW_PWM.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE MW_PWM.c -o obj/MW_PWM.o
[Compiling] MW_pigs.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE MW_pigs.c -o obj/MW_pigs.o
[Compiling] devices.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE devices.c -o obj/devices.o
[Compiling] sharedServer.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE sharedServer.c -o obj/sharedServer.o
[Compiling] v4l2_cam.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE v4l2_cam.c -o obj/v4l2_cam.o
[Compiling] IO_wrapperCameraboard.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE IO_wrapperCameraboard.c -o obj/IO_wrapperCameraboard.o
[Compiling] LED.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE LED.c -o obj/LED.o
[Compiling] MW_SPI.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE MW_SPI.c -o obj/MW_SPI.o
[Compiling] availableWebcam.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE availableWebcam.c -o obj/availableWebcam.o
[Compiling] picam.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE picam.c -o obj/picam.o
[Compiling] system.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE system.c -o obj/system.o
[Compiling] IO_wrapperLED.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE IO_wrapperLED.c -o obj/IO_wrapperLED.o
[Compiling] MW_I2C.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE MW_I2C.c -o obj/MW_I2C.o
[Compiling] MW_digitalIO.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE MW_digitalIO.c -o obj/MW_digitalIO.o
[Compiling] customFunction.c
gcc -c -g -O0 -D_DEBUG -Wall -I/opt/userland -I/opt/userland/host_applications/linux/libs/bcm_host/include -I/opt/userland/interface/vcos
-I/opt/userland/interface/vcos/pthreads -I/opt/userland/interface/vmcs_host/linux -I/opt/userland/host_applications/linux/apps/raspicam
-I/opt/nanomsg/include -Winline -pipe -D_DEBUG -D_MATLABIO_ -DMW_WEBSOC_INUSE customFunction.c -o obj/customFunction.o
make: Leaving directory '/opt/MATLAB/mw_server_v20.2.0'
>>

[Saloni Tak]

Hi, did you find the solution? I am getting the same error.

Answer 1

[Prasanth Sunkara]

Hi Sapir,

Looks like json C library is missing on your Raspberry Pi image.

Open a SSH session with your Pi and execute "sudo apt install libjson-c-dev". This would install the required json C library.

Now do r=raspi() from MATLAB.

Please let me know how this goes.

Thanks,

Prasanth

[Mahdi Barati]

Thank you for your guidance.

I had the same problem. I installed the package you mentioned, but the problem still exists with exactly the same error. Do you have any other suggestion?

[Prasanth Sunkara]

Just for me to understand this correctly, could you please share the complete error message/log that you got?