[fpc-pascal] question about _fpc_local_unwind

Jonas Maebe jonas at freepascal.org
Thu Feb 1 20:49:57 CET 2018


On 01/02/18 16:24, Matias Vara wrote:
> I partial answered my question by reading 
> https://www.freepascal.org/docs-html/ref/refse114.html. So I think 
> _fpc_local_unwind() is used to call the finally section when "Exit" is 
> executed in the "Try" section. It is not clear yet what the parameters 
> "frame,target: Pointer" are meant to. I checked the code generated in 
> Linux and is a bit different. It is base on the functions 
> FPC_PUSHEXCEPTADDR and FPC_POPADDRSTACK, which It seems much more clear. 
> Is it possible to generate a similar code in the case of Win64? In other 
> words, is it possible to tell the compiler "generate the 
> 'try-finally-end' block as in Linux"? I don't think so but It is worth 
> to ask.

No, it is not possible. On Win64 the compiler and RTL use so-called 
structured exception handling (SEH), which is required to interoperate 
with code generated by other compilers. See 
https://msdn.microsoft.com/en-us/library/windows/desktop/ms680657(v=vs.85).aspx 
for more information.


Jonas


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