Modify parameters of raw image

How can I modify parameters like "ISO speed","shutter ","timestamp".
For example : firstly, open a Raw file "test.CR2", then define LibRaw RawProcessor; i want to modify "shutter"of "test.CR2",my opinion is : RawProcessor.imagedata.other.shutter=8.9. But it does not work, the "test.CR2" file is not changed. how can i modify some parameters of RAW images.

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LibRaw opens files in read

LibRaw opens files in read-only mode and never modifies file data.

Try to use exiftool (or other tools) to modify image metadata.

-- Alex Tutubalin

How can I modifies raw image

I am doing a project about raw file processing.I do not know how to use C++ to write source code to modifies some parameters of RAW file . I have thought about the question for days. Can you give me some suggestion about it.
Thank you!

Raw Image to JPEG

I want to convert raw image to JPEG image including exif information,and get some information like DCT coefficients and so on. Can I do that using libraw library?

You may use LibRaw to read

You may use LibRaw to read RAW image and convert it to RGB bitmap (in memory).
To create JPEG image from this bitmap you'll need another software (LibJPEG or so)

-- Alex Tutubalin

Thanks for you reply. And I

Thanks for you reply. And I have another question.when I read the part of source code in libraw_cxx.cpp, the part of source code is :
char name[100], value[100];
utf2char(P[i].name,name);
utf2char(P[i].value,value);
if (!strcmp (name, "ISO"))
imgdata.other.iso_speed = atoi(value);
I am confused with this part of source code. when you developed this libraw library,how can you read "ISO speed" from Raw file to iso_speed variable of libraw?

This piece of code is related

This piece of code is related only to foveon images with own (non-EXIF) metadata format

-- Alex Tutubalin

How about other parameters

How about other parameters like "camera model" ,"camera make", like this Exif metadata, how can you read it to the libraw datastructure?

Make and model for these

Make and model for these files are parsed in other place.

-- Alex Tutubalin

For most (TIFF/EP) raw files,

For most (TIFF/EP) raw files, EXIF data is pointed by EXIF (34665) tag

-- Alex Tutubalin