hello, thanks for both of you for your reply. however, i'm still confused. actually my code will be use for simulation with Tossim; i have no real motes to implement. so, there is no precised platform to use. is it still a problem to use this "packed attribute" only for simulation purpose?
Best Regards. 2008/4/14 Urs Hunkeler <[EMAIL PROTECTED]>: > Hi, > > I thought that the compiler for the MSP430 architecture would simply > ignore the packet attribute. > > Even if the code executes on the motes, some compilers might ignore the > packet attribute. This results in the packet format not being equal on all > platforms, essentially meaning that motes from different platforms cannot > communicate. > > In TinyOS 2.x the nx_ types were introduced (like nx_uint8_t) that should > be used for packet structs. The nx_ types ensure the same endianeness and > the same data packing for all platforms. > > Cheers, > Urs > > > Philip Levis wrote: > > > On Apr 13, 2008, at 7:32 AM, fatima zohra wrote: > > > > > hello, > > > while reading the TinyOS programmation manual here, i came across > > > this important Hint : > > > > > > Programming Hint 14: Never, ever use the "packed" attribute. > > > > > > > > > can anyone explain to me why is it so important to notice this > > > problem ?? is it a big issue if we use packed attribute ? > > > > > > > Because if you used the packed attribute, words will not necessarily be > > aligned on word boundaries. Some architectures (such as the MSP430 of Telos > > nodes) require words be aligned on word boundaries, or return undefined > > results. So if you use the packed attribute, you could have code that > > cannot work correctly. > > > > Phil > > >
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