X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FNetwork%2Fnet_gui.hxx;h=d333918239f7c15ed76236613498172546f614c2;hb=a1031b052dd40ca3a4ea68dcd7f572b7d9e4bb24;hp=80764091b965d38c8b8aa407d9515d58b906f4d4;hpb=66ff2f15d35404640af825c3b49e189c257a2a6a;p=flightgear.git

diff --git a/src/Network/net_gui.hxx b/src/Network/net_gui.hxx
index 80764091b..d33391823 100644
--- a/src/Network/net_gui.hxx
+++ b/src/Network/net_gui.hxx
@@ -11,13 +11,16 @@
 #ifndef _NET_GUI_HXX
 #define _NET_GUI_HXX
 
+#include <simgear/misc/stdint.hxx>
 
-#ifndef __cplusplus                                                          
-# error This library requires C++
-#endif                                   
+// NOTE: this file defines an external interface structure.  Due to
+// variability between platforms and architectures, we only used fixed
+// length types here.  Specifically, integer types can vary in length.
+// I am not aware of any platforms that don't use 4 bytes for float
+// and 8 bytes for double.
 
 
-const int FG_NET_GUI_VERSION = 5;
+const uint32_t FG_NET_GUI_VERSION = 8;
 
 
 // Define a structure containing the top level flight dynamics model
@@ -33,38 +36,45 @@ public:
         FG_MAX_TANKS = 4
     };
 
-    int version;		// increment when data values change
-    int pad;                    // keep doubles 64-bit aligned for some
-                                // hardware platforms, such as the Sun
-                                // SPARC, which don't like misaligned
-                                // data
-
-    // Positions
-    double longitude;		// geodetic (radians)
-    double latitude;		// geodetic (radians)
-    float altitude;		// above sea level (meters)
-    float agl;			// above ground level (meters)
-    float phi;			// roll (radians)
-    float theta;		// pitch (radians)
-    float psi;			// yaw or true heading (radians)
+// Note: align fields properly and manually to avoid incompatibilities
+// between 32bit and 64bit CPUs. Make sure that each field is already
+// placed on an offset which is a multiple of the size of its data
+// type, i.e. uint32/float need to have on offset of 4, doubles need
+// an offset of 8. This guarantees that compilers will _not_ add
+// CPU-specific padding bytes. Whenever in doubt about padding rules,
+// check "data structure alignment" in Wikipedia/Google :).
+
+    uint32_t version;           // increment when data values change
+    uint32_t padding1;          // 4 padding bytes, so the next (64bit) var is aligned to 8
+
+    // Positions (note: offset for these doubles is already aligned to 8 - to avoid architecture specific alignments)
+    double longitude;           // geodetic (radians)
+    double latitude;            // geodetic (radians)
+
+    float altitude;             // above sea level (meters)
+    float agl;                  // above ground level (meters)
+    float phi;                  // roll (radians)
+    float theta;                // pitch (radians)
+    float psi;                  // yaw or true heading (radians)
 
     // Velocities
     float vcas;
-    float climb_rate;		// feet per second
+    float climb_rate;           // feet per second
 
     // Consumables
-    int num_tanks;		// Max number of fuel tanks
+    uint32_t num_tanks;         // Max number of fuel tanks
     float fuel_quantity[FG_MAX_TANKS];
 
     // Environment
-    time_t cur_time;            // current unix time
-    long int warp;              // offset in seconds to unix time
+    uint32_t cur_time;          // current unix time
+                                // FIXME: make this uint64_t before 2038
+    uint32_t warp;              // offset in seconds to unix time
     float ground_elev;          // ground elev (meters)
 
     // Approach
     float tuned_freq;           // currently tuned frequency
     float nav_radial;           // target nav radial
-    int in_range;               // tuned navaid is in range?
+    uint32_t in_range;           // tuned navaid is in range?
     float dist_nm;              // distance to tuned navaid in nautical miles
     float course_deviation_deg; // degrees off target course
     float gs_deviation_deg;     // degrees off target glide slope