Re: [avr-gcc-list] using malloc() in a SIGNAL function

[David Brown]

> Hey.
> I am just doing some code reviewing.
> I found that the code uses the malloc() function inside a SIGNAL
> function, as well as in the maincode.
> I did not find anything about if that is safe, in the documentation. But
> looking in the lst-file I can see no cli instructions.
> But of cource, it could be protected againts reentry in other ways. But
> is it?
>

I haven't looked at the avrlibc implementation, but in general malloc is not
re-entrant and must therefore be explicitly protected (such as by disabling
interrupts in the main program before calling it - assuming your program is
happy with disabling interrupts for inderminant times).  Of course, any use
of malloc in a small embedded system must be treated with extreme
suspicion - dynamic memory is on the list of "standard" C functionality that
should be avoided unless you are absolutely sure you need it and understand
all the consequences, along with things like printf and floating point
maths.