AP_Compass: fix C++ One Definition Rule violations

Two structs with the same name must have exactly the same definition, no matter where they occur in the program, otherwise the program is undefined. Move each sample register struct definition into the associated class definition so they are in a different namespace and no longer identically named, thus fixing this issue.
ArduPilot · Nov 21, 2023 · b8d50b1 · b8d50b1
1 parent 0d735ff
commit b8d50b1
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Showing 6 changed files with 21 additions and 19 deletions.
diff --git a/libraries/AP_Compass/AP_Compass_AK09916.cpp b/libraries/AP_Compass/AP_Compass_AK09916.cpp
@@ -58,13 +58,6 @@ extern const AP_HAL::HAL &hal;
 
 extern const AP_HAL::HAL &hal;
 
-struct PACKED sample_regs {
-    uint8_t st1;
-    int16_t val[3];
-    uint8_t tmps;
-    uint8_t st2;
-};
-
 AP_Compass_AK09916::AP_Compass_AK09916(AP_AK09916_BusDriver *bus,
                                         bool force_external,
                                         enum Rotation rotation)
@@ -477,7 +470,7 @@ bool AP_AK09916_BusDriver_Auxiliary::configure()
 
 bool AP_AK09916_BusDriver_Auxiliary::start_measurements()
 {
-    if (_bus->register_periodic_read(_slave, REG_ST1, sizeof(sample_regs)) < 0) {
+    if (_bus->register_periodic_read(_slave, REG_ST1, sizeof(AP_Compass_AK09916::sample_regs)) < 0) {
         return false;
     }
 

diff --git a/libraries/AP_Compass/AP_Compass_AK09916.h b/libraries/AP_Compass/AP_Compass_AK09916.h
@@ -75,6 +75,14 @@ class AP_Compass_AK09916 : public AP_Compass_Backend
 
     void read() override;
 
+    /* Must be public so the BusDriver can access its definition */
+    struct PACKED sample_regs {
+        uint8_t st1;
+        int16_t val[3];
+        uint8_t tmps;
+        uint8_t st2;
+    };
+
 private:
     AP_Compass_AK09916(AP_AK09916_BusDriver *bus, bool force_external,
                        enum Rotation rotation);

diff --git a/libraries/AP_Compass/AP_Compass_AK8963.cpp b/libraries/AP_Compass/AP_Compass_AK8963.cpp
@@ -49,11 +49,6 @@
 
 #define AK8963_MILLIGAUSS_SCALE 10.0f
 
-struct PACKED sample_regs {
-    int16_t val[3];
-    uint8_t st2;
-};
-
 extern const AP_HAL::HAL &hal;
 
 AP_Compass_AK8963::AP_Compass_AK8963(AP_AK8963_BusDriver *bus,
@@ -379,7 +374,7 @@ bool AP_AK8963_BusDriver_Auxiliary::configure()
 
 bool AP_AK8963_BusDriver_Auxiliary::start_measurements()
 {
-    if (_bus->register_periodic_read(_slave, AK8963_HXL, sizeof(sample_regs)) < 0) {
+    if (_bus->register_periodic_read(_slave, AK8963_HXL, sizeof(AP_Compass_AK8963::sample_regs)) < 0) {
         return false;
     }
 

diff --git a/libraries/AP_Compass/AP_Compass_AK8963.h b/libraries/AP_Compass/AP_Compass_AK8963.h
@@ -39,6 +39,12 @@ class AP_Compass_AK8963 : public AP_Compass_Backend
 
     void read() override;
 
+    /* Must be public so the BusDriver can access its definition */
+    struct PACKED sample_regs {
+        int16_t val[3];
+        uint8_t st2;
+    };
+
 private:
     AP_Compass_AK8963(AP_AK8963_BusDriver *bus,
                       enum Rotation rotation);

diff --git a/libraries/AP_Compass/AP_Compass_LSM9DS1.cpp b/libraries/AP_Compass/AP_Compass_LSM9DS1.cpp
@@ -47,11 +47,6 @@
 #define LSM9DS1M_INT_THS_L_M        0x32
 #define LSM9DS1M_INT_THS_H_M        0x33
 
-struct PACKED sample_regs {
-    uint8_t status;
-    int16_t val[3];
-};
-
 extern const AP_HAL::HAL &hal;
 
 AP_Compass_LSM9DS1::AP_Compass_LSM9DS1(AP_HAL::OwnPtr<AP_HAL::Device> dev,

diff --git a/libraries/AP_Compass/AP_Compass_LSM9DS1.h b/libraries/AP_Compass/AP_Compass_LSM9DS1.h
@@ -42,6 +42,11 @@ class AP_Compass_LSM9DS1 : public AP_Compass_Backend
     uint8_t _compass_instance;
     float _scaling;
     enum Rotation _rotation;
+
+    struct PACKED sample_regs {
+        uint8_t status;
+        int16_t val[3];
+    };
 };
 
 #endif