To what granularity are expressions in function call parameters interleaved?
void mad(cow_string a, cow_string b);
cow_string s("moo");
cow_string s1 = s;
cow_string s2 = s;
mad(s1+="haha",s2+="hahaha");

// In some header file:
void f( T1*, T2* );

// In some implementation file:
f( new T1, new T2 );

allocate memory for the T1
construct the T1
allocate memory for the T2
construct the T2
call f()

allocate memory for the T1
allocate memory for the T2
construct the T1
construct the T2
call f()

void mad(cow_string & a, cow_string & b);
cow_string s("moo");
cow_string s1 = s;
cow_string s2 = s;
mad(s1+="haha",s2+="hahaha");

int a = 5;
foo(a+=9*4, a+=13/2);