Build failure due to const cast

[Carmelo DrRaw]

My automated AppImage packages are failing due to the following build error:

/sources/rtengine/imageio.cc: In member function ‘int rtengine::ImageIO::loadJPEGFromMemory(const char*, int)’:
/sources/rtengine/imageio.cc:377:26: error: invalid conversion from ‘const unsigned char*’ to ‘unsigned char*’ [-fpermissive]
     jpeg_mem_src(&cinfo, reinterpret_cast<const unsigned char *>(buffer), bufsize);
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /sources/rtengine/iccjpeg.h:20:0,
                 from /sources/rtengine/imageio.cc:41:
/usr/include/jpeglib.h:1008:14: note:   initializing argument 2 of ‘void jpeg_mem_src(j_decompress_ptr, unsigned char*, long unsigned int)’
 EXTERN(void) jpeg_mem_src JPP((j_decompress_ptr cinfo,

It seems there is an unnecessary cast to const unsigned char *

[agriggio]

what version of jpeglib?

[Carmelo DrRaw]

I am using libjpeg-turbo 1.2.90-8, which is the package provided by the CentOS 7 repositories.

[agriggio]

does this patch work for you?

diff --git a/rtengine/imageio.cc b/rtengine/imageio.cc
--- a/rtengine/imageio.cc
+++ b/rtengine/imageio.cc
@@ -374,7 +374,7 @@
     jpeg_decompress_struct cinfo;
     jpeg_create_decompress(&cinfo);
     //rt_jpeg_memory_src (&cinfo, (const JOCTET*)buffer, bufsize);
-    jpeg_mem_src(&cinfo, reinterpret_cast<const unsigned char *>(buffer), bufsize);
+    jpeg_mem_src(&cinfo, const_cast<unsigned char *>(reinterpret_cast<const unsigned char *>(buffer)), bufsize);

     /* We use our private extension JPEG error handler.
        Note that this struct must live as long as the main JPEG parameter

‌

[Carmelo DrRaw]

I will check later today and report back here.