Inline variables are only available in C++17 and above

src/bindgen/config.rs

@@ -714,6 +714,8 @@ pub struct ConstantConfig {
     pub allow_static_const: bool,
     /// Whether a generated constant should be constexpr in C++ mode.
     pub allow_constexpr: bool,
+    /// Whether a generated constexpr should be inlined
+    pub allow_inline: bool,
     /// Sort key for constants
     pub sort_by: Option<SortKey>,
 }
@@ -723,6 +725,7 @@ impl Default for ConstantConfig {
         ConstantConfig {
             allow_static_const: true,
             allow_constexpr: true,
+            allow_inline: true,
             sort_by: None,
         }
     }

src/bindgen/ir/constant.rs

@@ -726,7 +726,13 @@ impl Constant {
                 }
 
                 if config.constant.allow_static_const {
-                    out.write(if in_body { "inline " } else { "static " });
+                    out.write(if in_body && config.constant.allow_inline {
+                        "inline "
+                    } else if !in_body {
+                        "static "
+                    } else {
+                        ""
+                    });
                 }
 
                 if let Type::Ptr { is_const: true, .. } = self.ty {

template.toml

@@ -129,6 +129,7 @@ private_default_tagged_enum_constructor = false
 [const]
 allow_static_const = true
 allow_constexpr = false
+allow_inline = true # Set to 'false' if compiling before C++17
 sort_by = "Name"
 
 

tests/expectations/no_inline_constant_constexpr.compat.c

@@ -0,0 +1,19 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define CONSTANT_I64 216
+
+#define CONSTANT_FLOAT32 312.292
+
+#define DELIMITER ':'
+
+#define LEFTCURLY '{'
+
+typedef struct {
+  int32_t x;
+} Foo;
+#define Foo_CONSTANT_I64_BODY 216
+
+#define SomeFoo (Foo){ .x = 99 }

tests/expectations/no_inline_constant_constexpr.cpp

@@ -0,0 +1,23 @@
+#include <cstdarg>
+#include <cstdint>
+#include <cstdlib>
+#include <ostream>
+#include <new>
+
+static const int64_t CONSTANT_I64 = 216;
+
+static const float CONSTANT_FLOAT32 = 312.292;
+
+static const uint32_t DELIMITER = ':';
+
+static const uint32_t LEFTCURLY = '{';
+
+struct Foo {
+  int32_t x;
+  static const int64_t CONSTANT_I64_BODY;
+};
+const int64_t Foo::CONSTANT_I64_BODY = 216;
+
+static const Foo SomeFoo = Foo{
+  /* .x = */ 99
+};

tests/expectations/no_inline_constant_constexpr.pyx

@@ -0,0 +1,21 @@
+from libc.stdint cimport int8_t, int16_t, int32_t, int64_t, intptr_t
+from libc.stdint cimport uint8_t, uint16_t, uint32_t, uint64_t, uintptr_t
+cdef extern from *:
+  ctypedef bint bool
+  ctypedef struct va_list
+
+cdef extern from *:
+
+  const int64_t CONSTANT_I64 # = 216
+
+  const float CONSTANT_FLOAT32 # = 312.292
+
+  const uint32_t DELIMITER # = ':'
+
+  const uint32_t LEFTCURLY # = '{'
+
+  ctypedef struct Foo:
+    int32_t x;
+  const int64_t Foo_CONSTANT_I64_BODY # = 216
+
+  const Foo SomeFoo # = <Foo>{ 99 }

tests/expectations/no_inline_constant_constexpr_both.compat.c

@@ -0,0 +1,19 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define CONSTANT_I64 216
+
+#define CONSTANT_FLOAT32 312.292
+
+#define DELIMITER ':'
+
+#define LEFTCURLY '{'
+
+typedef struct Foo {
+  int32_t x;
+} Foo;
+#define Foo_CONSTANT_I64_BODY 216
+
+#define SomeFoo (Foo){ .x = 99 }

tests/expectations/no_inline_constant_constexpr_tag.compat.c

@@ -0,0 +1,19 @@
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+#define CONSTANT_I64 216
+
+#define CONSTANT_FLOAT32 312.292
+
+#define DELIMITER ':'
+
+#define LEFTCURLY '{'
+
+struct Foo {
+  int32_t x;
+};
+#define Foo_CONSTANT_I64_BODY 216
+
+#define SomeFoo (Foo){ .x = 99 }

tests/expectations/no_inline_constant_constexpr_tag.pyx

@@ -0,0 +1,21 @@
+from libc.stdint cimport int8_t, int16_t, int32_t, int64_t, intptr_t
+from libc.stdint cimport uint8_t, uint16_t, uint32_t, uint64_t, uintptr_t
+cdef extern from *:
+  ctypedef bint bool
+  ctypedef struct va_list
+
+cdef extern from *:
+
+  const int64_t CONSTANT_I64 # = 216
+
+  const float CONSTANT_FLOAT32 # = 312.292
+
+  const uint32_t DELIMITER # = ':'
+
+  const uint32_t LEFTCURLY # = '{'
+
+  cdef struct Foo:
+    int32_t x;
+  const int64_t Foo_CONSTANT_I64_BODY # = 216
+
+  const Foo SomeFoo # = <Foo>{ 99 }

tests/rust/no_inline_constant_constexpr.rs

@@ -0,0 +1,14 @@
+pub const CONSTANT_I64: i64 = 216;
+pub const CONSTANT_FLOAT32: f32 = 312.292;
+pub const DELIMITER: char = ':';
+pub const LEFTCURLY: char = '{';
+#[repr(C)]
+struct Foo {
+    x: i32,
+}
+
+pub const SomeFoo: Foo = Foo { x: 99, };
+
+impl Foo {
+    pub const CONSTANT_I64_BODY: i64 = 216;
+}

tests/rust/no_inline_constant_constexpr.toml

@@ -0,0 +1,6 @@
+[const]
+allow_constexpr = false
+allow_inline = false
+
+[struct]
+associated_constants_in_body = true