xref: /llvm-project/clang/test/C/C99/float_h-characteristics.c (revision f6198686b866d0a1efe7ce88f71c4293930c2dfe)
1 // RUN: %clang_cc1 -verify -std=c99 -ffreestanding %s
2 // RUN: %clang_cc1 -verify -std=gnu89 -ffreestanding %s
3 // RUN: %clang_cc1 -verify -std=c89 -ffreestanding %s
4 // expected-no-diagnostics
5 
6 /* WG14 ???: Clang 16
7  * Additional floating-point characteristics in <float.h>
8  *
9  * NB: the original paper number is unknown, this was gleaned from the editor's
10  * report in the C99 foreword. There were two new additions to <float.h> in
11  * C99, this is testing that we support both of them.
12  *
13  * Clang added the macros at least as far back as Clang 3.0, but it wasn't
14  * until Clang 16.0 that we stopped accidentally providing FLT_EVAL_METHOD in
15  * C89 (strict) mode.
16  */
17 
18 #include <float.h>
19 
20 // We expect all the definitions in C99 mode.
21 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
22 #define EXPECT_DECIMAL_DIG
23 #define EXPECT_FLT_EVAL_METHOD
24 #endif
25 
26 // If we're not in C99 mode, we still expect the definition of DECIMAL_DIG
27 // unless we're in strict ansi mode.
28 #if !defined(EXPECT_DECIMAL_DIG) && !defined(__STRICT_ANSI__)
29 #define EXPECT_DECIMAL_DIG
30 #endif
31 
32 #if defined(EXPECT_DECIMAL_DIG)
33   #if !defined(DECIMAL_DIG)
34     #error "DECIMAL_DIG missing"
35   #endif
36 #else
37   #if defined(DECIMAL_DIG)
38     #error "DECIMAL_DIG provided when not expected"
39   #endif
40 #endif
41 
42 #if defined(EXPECT_FLT_EVAL_METHOD)
43   #if !defined(FLT_EVAL_METHOD)
44     #error "FLT_EVAL_METHOD missing"
45   #endif
46 #else
47   #if defined(FLT_EVAL_METHOD)
48     #error "FLT_EVAL_METHOD provided when not expected"
49   #endif
50 #endif
51