From 01cad1c4aa4b934d3724c435a5b0e1951687ec79 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Mon, 19 Dec 2022 08:01:41 +1100
Subject: [PATCH] SITL: added SIM_GPS_LOG_NUM

for replaying GPS logs recorded with --enable-gps-logging
---
 libraries/SITL/SIM_GPS.cpp | 2 +-
 libraries/SITL/SITL.cpp    | 2 ++
 libraries/SITL/SITL.h      | 3 +++
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/libraries/SITL/SIM_GPS.cpp b/libraries/SITL/SIM_GPS.cpp
index 5e5b732b5f..0b2735a197 100644
--- a/libraries/SITL/SIM_GPS.cpp
+++ b/libraries/SITL/SIM_GPS.cpp
@@ -1023,7 +1023,7 @@ void GPS::update_file()
 {
     static int fd[2] = {-1,-1};
     static uint32_t base_time[2];
-    const uint16_t lognum = 9;
+    const uint16_t lognum = uint16_t(_sitl->gps_log_num.get());
     if (instance > 1) {
         return;
     }
diff --git a/libraries/SITL/SITL.cpp b/libraries/SITL/SITL.cpp
index 954cd23588..f4387c2cd1 100644
--- a/libraries/SITL/SITL.cpp
+++ b/libraries/SITL/SITL.cpp
@@ -376,6 +376,8 @@ const AP_Param::GroupInfo SIM::var_gps[] = {
     AP_GROUPINFO("INIT_LON_OFS",  46, SIM,  gps_init_lon_ofs, 0),
     AP_GROUPINFO("INIT_ALT_OFS",  47, SIM,  gps_init_alt_ofs, 0),
 
+    AP_GROUPINFO("GPS_LOG_NUM",   48, SIM,  gps_log_num, 0),
+
     AP_GROUPEND
 };
 #endif  // HAL_SIM_GPS_ENABLED
diff --git a/libraries/SITL/SITL.h b/libraries/SITL/SITL.h
index 7a2151a52a..a3d46d84a6 100644
--- a/libraries/SITL/SITL.h
+++ b/libraries/SITL/SITL.h
@@ -209,6 +209,9 @@ public:
     AP_Float gps_init_lon_ofs;
     AP_Float gps_init_alt_ofs;
 
+    // log number for GPS::update_file()
+    AP_Int16 gps_log_num;
+
     AP_Float batt_voltage; // battery voltage base
     AP_Float batt_capacity_ah; // battery capacity in Ah
     AP_Int8  rc_fail;     // fail RC input