As a way to relax, I decide to do some dig on perl internal during my holiday. The first I try to do is Macro dSP which I often use in Inline::C. what it actually does behind dSP? Here is some clues: 
#define dSP             SV **sp = PL_stack_sp        
#define PL_stack_sp             (vTHX->Istack_sp)

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It seems that vTHX is a perlinterpreter instance, but I can't find definition of perlinterpreter struct and definition of Istack_sp in perl source directory.

Please help me!



I am trying to improve my English skills, if you see a mistake please feel free to reply or /msg me a correction

In reply to what definition of Istack_sp by xiaoyafeng

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