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multiple_return_values [2019/04/19 21:13] – korshun | multiple_return_values [2019/04/19 22:41] – korshun | ||
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====== Multiple return values convention ====== | ====== Multiple return values convention ====== | ||
- | Some ACSUtils functions return multiple values (e.g. [[math# | + | Some ACSUtils functions return multiple values (e.g. [[math# |
ACSUtils uses a convention to fake returning multiple values from a function. The convention is as follows: there are 8 global variables with names '' | ACSUtils uses a convention to fake returning multiple values from a function. The convention is as follows: there are 8 global variables with names '' | ||
- | Here's an example: | + | Here's an example, '' |
< | < | ||
Line 13: | Line 13: | ||
</ | </ | ||
+ | <note warning> | ||
+ | You should retrieve the return values **as soon as possible**, or else they may get overwritten by other functions that return multiple values. | ||
+ | Don't do this: | ||
+ | < | ||
+ | SomeFunctionWithMultipleReturnValues(...); | ||
+ | SomeOtherFunction(r1); | ||
+ | int b = r2; | ||
+ | </ | ||
+ | Because '' | ||
+ | < | ||
+ | SomeFunctionWithMultipleReturnValues(...); | ||
+ | int a = r1; | ||
+ | int b = r2; | ||
+ | SomeOtherFunction(a); | ||
+ | </ | ||
+ | </ | ||
+ | <note important> | ||
+ | |||
+ | < | ||
+ | ParseFixed(" | ||
+ | int error = r1; | ||
+ | int result = r2; // no compiler error, despite assigning a fixed to int | ||
+ | </ | ||
+ | |||
+ | </ | ||
+ | |||
+ | But overwriting argument variables immediately after calling the function is valid: | ||
+ | < | ||
+ | RotateVector(x, | ||
+ | x = r1; | ||
+ | y = r2; | ||
+ | </ | ||
+ | |||
+ | An example of a function returning three values: | ||
+ | < | ||
+ | normalize3d(x, | ||
+ | int newX = r1; | ||
+ | int newY = r2; | ||
+ | int newZ = r3; | ||
+ | </ | ||