gcc/testsuite/gcc.dg/cpp/if-cexp.c - gcc - Git at Google

 /* { dg-do preprocess } */

 /* Test the ? : opearator, for precedence and both true and false.  */

 #if  1 ? 1 ? 2 : 0 : 0
 #error OK	/* { dg-error "OK" "nested ? :" } */
 #endif

 #if  ((0) ? (1) ? (2) : (3) : (4) ? (5): (6)) == 5
 #error OK	/* { dg-error "OK" "nested ? : with parens" } */
 #endif
	/* { dg-do preprocess } */

	/* Test the ? : opearator, for precedence and both true and false. */

	#if 1 ? 1 ? 2 : 0 : 0
	#error OK /* { dg-error "OK" "nested ? :" } */
	#endif

	#if ((0) ? (1) ? (2) : (3) : (4) ? (5): (6)) == 5
	#error OK /* { dg-error "OK" "nested ? : with parens" } */
	#endif