objective c - Struct to NSData between Mac and iOS -

i have been working on problem while, have app running on mac, has co-ordinate data stored in struct this:

struct xyz {   float x;   float y;   float z; };  struct xy {   float x;   float y; };  struct object {   struct xyz *myxyz;   struct xy *myxy; }; 

this works expected, add struct nsdata so:

struct object aninitialteststruct; nsmutabledata *mytestdataout = [nsmutabledata datawithbytes:&aninitialteststruct length:64 freewhendone:no]; bool = [mytestdataout writetofile:[nsstring stringwithformat:@"%@/filename.dat", docsdirectory] atomically:yes]; 

this works expected, file , looks there data in (for reference have used pointers , malloc aninitialteststruct still don't desired result)

now on iphone, copy file project, , this:

nsstring *filepath = [[nsbundle mainbundle] pathforresource:@"filename" oftype:@"dat"]; nsdata *myvecnsdata = [[nsdata alloc] initwithcontentsoffile:filepath options:nsdatareadinguncached error:&error]; if ( error ) {     nslog(@"%@", error); } 

i don't correct data back. interestingly if run initwithcontents method on mac , read file in there appears ok.

so i'm thinking there different on iphone / mac way deals filesystem.... i've tried encoding data using nskeyedarchiver, exception stating "incomprehensible archive....."

for case of "object" structure have store "xy" , "xyz" structures separately, example in dictionary:

    struct object aninitialteststruct;     nsdictionary *structuredataasdictionary = [nsdictionary dictionarywithobjectsandkeys:                                      [nsmutabledata datawithbytes:aninitialteststruct.myxy length:sizeof(xy)], @"xy key",                                      [nsmutabledata datawithbytes:aninitialteststruct.myxyz length:sizeof(xyz)], @"xyz key",                                      nil];     nsdata *mytestdataout = [nskeyedarchiver archiveddatawithrootobject:structuredataasdictionary];     bool = [mytestdataout writetofile:[nsstring stringwithformat:@"%@/filename.dat", docsdirectory] atomically:yes]; 

and decoding this:

    struct object aninitialteststruct;     nsstring *filepath = [[nsbundle mainbundle] pathforresource:@"filename" oftype:@"dat"];     nsdata *myvecnsdata = [[nsdata alloc] initwithcontentsoffile:filepath options:nsdatareadinguncached error:&error];     if ( error ) {         nslog(@"%@", error);     }     // retrieving dictionary nsdata     nsdictionary *structuredataasdictionary = [nskeyedunarchiver unarchiveobjectwithdata:myvecnsdata];     // allocating memory myxy , myxyz fields     aninitialteststruct.myxy = (xy*)malloc(sizeof(xy));     if (aninitialteststruct.myxy == null) {         // error handling     }     aninitialteststruct.myxyz = (xyz*)malloc(sizeof(xyz));     if (aninitialteststruct.myxyz == null) {         // error handling     }     // filling myxy , myxyz fields read data     [[structuredataasdictionary objectforkey:@"xy key"] getbytes:aninitialteststruct.myxy];     [[structuredataasdictionary objectforkey:@"xyz key"] getbytes:aninitialteststruct.myxyz];