使用libexif将exif数据写入jpg

I'm trying to use libexif to write exif data into a jpeg file. I'm pretty much following the example provided with it. I can understand all the Exif data blocks being written and everything, but how do I load the jpeg data like they suggested? (using libjpeg). I couldn't find a function that would directly let me import the jpeg as char. My code works fine if I include a dummy jpg with it like shown below.I'm trying to use libexif to write exif data in