llvm/clang/test/Preprocessor/c99-6_10_3_4_p7.c

// Example from C99 6.10.3.4p7

// RUN: %clang_cc1 -E %s | FileCheck -strict-whitespace %s

#define t(x,y,z) x ## y ## z 
int j[] = { t(1,2,3), t(,4,5), t(6,,7), t(8,9,), 
t(10,,), t(,11,), t(,,12), t(,,) }; 

// CHECK: int j[] = { 123, 45, 67, 89,
// CHECK: 10, 11, 12, };