modernc.org/ccgo/v3@v3.16.14/lib/testdata/gcc-9.1.0/gcc/testsuite/gcc.c-torture/compile/981001-4.c (about)

     1  #define P(a,b) P1(a,b)
     2  #define P1(a,b) a##b
     3  
     4  #define ONCE(x, y) (x ?: (x = y()))
     5  #define PREFIX
     6  
     7  extern int P(PREFIX, init) (void);
     8  
     9  int
    10  fun(void)
    11  {
    12    static int memo;
    13    return ONCE(memo, P(PREFIX, init));
    14  }