函数参数是结构，在调用时为其成员分配一个值

Question

Take for instance the following example of calling a function, and assigning a value to one of its parameters at call time:

int MyFunction(int flag, float value);

MyFunction(myFlag=666, 3.14);

It's legal, though perhaps dangerous, to assign values to variables in a function call's parameter list.

How can I do something similar when a function's parameter may be a structure?

typedef struct
{
  int i, j;
  float k;
} my_struct;

int MyFunction(my_struct values);

myValues.i = 666;
myValues.k = 3.14;

MyFunction(myValues);

// how about this instead:
MyFunction({myValues.j=777});     // or something similar?

Answer 1

您可以为变量分配复合文字：

MyFunction(myValues = (my_struct) {myValues.i, .j=777, myValues.k});

Answer 2

The comma operator can be used in function arguments. You need some extra parentheses so it doesn't look like an argument-separating comma:

MyFunction((myValues.j=777, myValues));