OpenCV 2.2 CrossCompilation for ARM – fixes (Bug #842)

Hello there,
A few days ago we tried to compile the newest OpenCV release (2.2) for our OMAP cpu using the CodeSourcery g++ compiler. There are, again, a few issues that need to be solved in order to guarantee compilation of OpenCV without any troubles.

First of all, the number of “errors” has been greatly diminished since the last few releases. It’s quite nice to see, that our comments are regarded useful by you folks!

Since were not completely through with the cross compilation for the ARM processor using our g++ CodeSourcery compiler the following fixes aren’t complete. Since we aren’t using a unix- or windows-like system, most of the errors seem to come from platform dependencies.

1. /include/opencv2/core/internal.hpp
   - #include <sys/mman.h> can not be found: we had to remove this
   line since this header could not be found. The removal had no
   effect – it seems that this header isn’t needed at all.
2. define of ‘expl’ is missing in /modules/ml/src/gbt.cpp
   - at line 14-16 we had to remove the #if ANDROID flag in order to
   use #define expl(x) exp(x).
3. /modules/core/src/rand.cpp: issues with pthread
   - This was actual already a problem in previous version of
   OpenCV, but we did never commit the “bug”. From line 634-668 we
   had to remove the functionality since this won’t work on our
   system. We inserted a new define NO_OS that switches between
   implementations.

 1#ifdef NO_OS
 2RNG& theRNG()
 3{
 4    CV_Assert(FALSE); // runtime stop if this one is really used! psa
 5    RNG* rng = NULL;
 6    return *rng;
 7}
 8#else
 9static pthread_key_t tlsRNGKey = 0;
10
11static void deleteRNG(void* data)
12{
13    delete (RNG*)data;
14}
15
16RNG& theRNG()
17{
18    if( !tlsRNGKey )
19    {
20        int errcode = pthread_key_create(&tlsRNGKey, deleteRNG);
21        CV_Assert(errcode == 0);
22    }
23    RNG* rng = (RNG*)pthread_getspecific(tlsRNGKey);
24    if( !rng )
25    {
26        rng = new RNG;
27        pthread_setspecific(tlsRNGKey, rng);
28    }
29    return *rng;
30}
31#endif

There are a few more issues that need addressing, but at the moment, the ones above are the most important.

Regards
Matthias