Error writing to file using Jpeg_write.mexmaci64

Recently i moved my project to mac OS so i needed to compile jpeg toolbox c++ files and create jpeg_read.mexmaci64 and jpeg_write.mexmaci64.

after a lot of search and try, finally i did that.

when i used mex for jpeg_write, the compilation successfully completed but there was a warning to. i dont know it is important or not.

mex -compatibleArrayDims -I/usr/local/opt/jpeg/include ...
    -I/usr/local/opt/gdcm/include/gdcm-3.0/gdcmjpeg ...
    jpeg_write.c ...
    -L/usr/local/opt/jpeg/lib -L/usr/local/opt/gdcm/lib ...
    -ljpeg -lgdcmjpeg16
Building with 'Xcode with Clang'.
/Users/venus/Downloads/jpeg_toolbox/jpeg_write.c:357:42: warning: passing 'char *' to parameter of type 'const JOCTET *' (aka 'const unsigned char *') converts between pointers to integer types with different sign [-Wpointer-sign]
     jpeg_write_marker(&cinfo, JPEG_COM, comment, strlen-1);
                                         ^~~~~~~
/usr/local/opt/jpeg/include/jpeglib.h:1031:22: note: passing argument to parameter 'dataptr' here
             const JOCTET * dataptr, unsigned int datalen));
                            ^
1 warning generated.

MEX completed successfully.

but when i run my project MATLAB returns me an error when it comes to jpeg_write.

Error using jpeg_write
Error writing to file.

this is the code from my project when the error happens:

jpeg_write(jpegobj,[dirStego '/' regexprep(files(w).name,'.png','.jpg')]);

can anyone help me? im confused!!

[Walter Roberson]

Try

jpeg_write(jpegobj, uint8([dirStego '/' regexprep(files(w).name,'.png','.jpg')]));

[Venus R]

i tried but it shows another error:

Error using jpeg_write
Filename must be a string.

[Venus R]

I editted my question and added a picture of the error i mentioned in the question.

[Walter Roberson]

I found updated toolkit source:

https://digitnet.github.io/m4jpeg/m4jpeg-tool/phil-sallee-matlab-jpeg-toolbox.htm

By itself it does not solve the problems you encountered.

[Walter Roberson]

I was able to get the code to compile without warning, but it crashed my MATLAB as soon as I did a jpeg_write, so unfortunately I do not have anything useful to hand over.

[Venus R]

Thank you for your help and try Walter. I tried the jpeg toolbox from the link. but nothing changed.

i have no idea why im getting this error.

if you find out the reason and the solution in the future, please let me know.

i will appreciate it.