Hardware Design: SIE

Hardware Design: SIE Git Source Tree

1	Examples from http://www.wellho.net/mouth/1844_Calling-functions-in-C-from-your-Lua-script-a-first-HowTo.html
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4	The code is very similar, but you'll notice six additions - in the Lua:
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6	a) We have added a parameter to the call to dothis in the Lua
7	b) We have added an assignment to collect a return value from the C
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9	summat = cstuff.dothis(value)
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11	c) We have printed out these values
12	print ("Values in Lua now",value, summat)
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15	and in the C:
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17	d) We have used lua_tonumber to collect a numeric value that was passed from the Lua to the C; you'll note that all such numbers are treated as doubles. The parameter "1" indicates 1 down - i.e. top of - the state stack.
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19	double trouble = lua_tonumber(L, 1);
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21	e) We have performed a calculation (representative of something being done in the C code) and pushed the result of this back onto the Lua state stack so that it can be picked up once we have returned from the C to the Lua
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23	lua_pushnumber(L, 16.0 - trouble);
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25	f) We have changed return 0 into return 1 to indicate that one result is being returned.
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27	return 1; }
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