iphone - making ios 6 app project compatible with iOS 5 - backwards -

iphone - making ios 6 app project compatible with iOS 5 - backwards -

this question ios 5 xcode 4.2. that's running ios development.

i have download sample project git hub instaoverlay , when @ target says "6.0" switched 5.0 , tried compiling code. wasn't able go far can see screenshot. tons , tons of errors.

so question is, there problem code or projects made ios 6 can never made run on ios 5? thought users able create apps backward compatible?

any suggestions

general answer

yes, apps can made backwards compatible ios5 or earlier. "can be" beingness of import grab here -- doing can time consuming, depending on application does, apis uses, etc. on other handle, quite simple projects can work, if utilize standard apis available without much alter since origin of (ios) time.

obviously if app uses ios6 features, you're stuck. otherwise, yes, can it, prepared take time doing -- not writing/alterting code, testing it.

so far you're concerned, yes, project 'broken', mean not written older versions of ios. if simple changing project setting!

here's few strategies making backwards-compatible apps:

where variants on api exist, different methods having different compatability, utilize compatible variants. example, nsfilemanager methods appeared in newer versions of ios, older variations still work. apple tend willy-nilly publish source code (ime) uses newer code without proviso "btw, won't work on older versions of ios" care needed

if want create functionality appear on newer ios versions, need run-time check desired methods/apis available, , utilize them when are. in these cases need careful linking project , 'weak link' items.

if need ios3 compatability, can't utilize arc; has old-style memory management. ios4 supports arc, few runtime limitations: auto-nilling of references isn't supported.

movie playing classic illustration of newer , improve apis beingness available older apis still beingness around. older mpmovieplayercontroller pre-ios4, mpmovieplayerviewcontroller appeared in ios4 (note word 'view' -- it's fledged uiviewcontroller). typically want utilize latter, ios3 compatability you'd decide utilize former based on runtime check.

specific answer

your problem cv_xadd: looks preprocessor definition #defined somewhere compiler isn't picking up. hint, seek looking definition of cv_xadd searching #define cv_xadd. if can't find that, seek looking cv_xadd , looking definition in results.

have tried googling terms 'cv_xadd expected expression'? number of hits relating problem.

your project using c++ adds more complexity mix!

iphone ios xcode xcode4.2