Hi, I found this:
http://pastebin.com/T4jkeE6F in a zip file called vfp.tar.bz4 somewhere on the web, it seems not maintained since ages but obviously it must have compiled at some time in the past. I am tying to see whether I can hack a quick and dirty program that is able to open an v4l device and do some simple things and maybe grab a frame (if I can somehow manage to keep the motivation level above the frustration level for a long enough time). _IOR is defined as #define _IOR(x,y,t) (IOC_OUT|((sizeof(t)&IOCPARM_MASK)<<16)|(x<<8)|y) and in FPC I have found a *function* in kernelioctl.pp with the same name that seems to serve the same purpose, except that it is a function and not a macro. And here comes the problem: #define VIDIOCGCAP _IOR('v',1,struct video_capability) /* Get capabilities */ obviously the following will not compile since the function cannot run at compile time: const VIDIOCGCAP = _IOR(Ord('v'), 1, SizeOf(video_capability)); in the above mentioned ten years old pascal file there is the following: //define[_IOR(][,#1,#2)][_IOC(2,ord('#0'),#1,sizeof(#2));] const VIDIOCGCAP = _IOR(v,1,video_capability); The first line looks like it is meant to be understood by some kind of prepocessor but FPC does not seem to understand this. The zip file also contains a folder with something that looks like it is a macro processor that is meant to be used to process this file and a makefile to start the entire thing but there are compile errors and and the perceived hack-level of this entire thing is quite high. What would be the most reasonable thing for me to have the handful of constants defined that I need (I don't need the entire API, only the most basic things to open my webcam and grab a frame¹). Should I use variables and initialize them at runtime? Or should I define functions instead of constants? How should I now proceed? Should I try to make this entire thing (including its macro pocessor) compile with a current FPC? I don't really like this idea because v4l1 is deprecated anyways. And the separate macro processor and the makefile also somehow does not look tlike the right approach to me, there must be a better way. And I don't need the entire full blown thing, only a small subset for a small quick and dirty program to try a little idea of mine (might prove to be throw-away code anyways). _____ ¹) my current solution is just piping RGB data from streamer through a named pipe to my application, I just wanted to know if i could get rid of this external process and communicate directly with the camera and also be able to control gain and exposure directly and in real time, therefore I am investigating v4l/v4l2. I haven't found any other v4l implementation for FPC. _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
