clang/test/C/C99/n570.c

   1 // RUN: %clang_cc1 -verify -std=c99 %s
   2 // RUN: %clang_cc1 -E -std=c99 %s | FileCheck %s
   3 // expected-no-diagnostics
   4
   5 /* WG14 N570: Yes
   6  * Empty macro arguments
   7  *
   8  * NB: the original paper is not available online anywhere, so the test
   9  * coverage is coming from what could be gleaned from the C99 rationale
  10  * document. In C89, it was UB to pass no arguments to a function-like macro,
  11  * and that's now supported in C99.
  12  */
  13
  14 #define TEN 10
  15 #define U u
  16 #define I // expands into no preprocessing tokens
  17 #define L L
  18 #define glue(a, b) a ## b
  19 #define xglue(a, b) glue(a, b)
  20
  21 const unsigned u = xglue(TEN, U);
  22 const int i = xglue(TEN, I);
  23 const long l = xglue(TEN, L);
  24
  25 // CHECK: const unsigned u = 10u;
  26 // CHECK-NEXT: const int i = 10;
  27 // CHECK-NEXT: const long l = 10L;
  28
  29 _Static_assert(u == 10U, "");
  30 _Static_assert(i == 10, "");
  31 _Static_assert(l == 10L, "");