Warning
Casting pointers can be dangerous if not done carefully, leading to potential undefined behaviour.
Pointer:as(type) method
Casts the current Pointer to the provided Pointer type.
Parameters
type
A value indicating the new pointer type, any of the following values :
- An aggregate C definition type : Struct, Union or an [ ] Array
- A
stringthat indicates the primitive C pointer type to be casted to :C primitive pointer strings unsigned char*,char*,wchar_t*,bool*,short*,unsigned short*int*,unsigned int*,long*,long long*unsigned long*unsigned long long*size_t*int16_t*int32_t*int64_t*,uint16_t*,uint32_t*,uint64_t*,float*,double*string,void*,wstring
Return value
The function returns a new Pointer pointing to the same memory address but casted to the provided C type.Example
local c = require "c"
-- Creates a Pointer to a Buffer in memory (Pointer of type "void*")
local buff = sys.Buffer("\x48\x65\x6C\x6C\x6F\x20\x4C\x75\x61\x52\x54\x20\x21\x00")
local c_ptr = c.Pointer(buff)
-- always false : we are comparing a memory pointer to a Lua string value
print(c_ptr == "Hello LuaRT !")
-- always true : converts the memory pointer to a Lua string value
local lua_string = tostring(c_ptr:as("string")) -- c_ptr is casted to a "string" before
print(lua_string == "Hello LuaRT !")