From 16fc3e5774069c77ff9ec304555e065ff08e4c6f Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Fri, 16 Oct 2020 17:41:19 +0300
Subject: Process: add get_exit_code()

---
 include/winapi/process.hpp |  4 +++-
 src/process.cpp            | 20 ++++++++++++++++++--
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/include/winapi/process.hpp b/include/winapi/process.hpp
index 2614c0f..f404b33 100644
--- a/include/winapi/process.hpp
+++ b/include/winapi/process.hpp
@@ -48,7 +48,9 @@ public:
     static Process create(const CommandLine&);
     static Process create(const CommandLine&, IO);
 
-    void wait();
+    void wait() const;
+
+    int get_exit_code() const;
 
 private:
     explicit Process(Handle&& handle) : m_handle{std::move(handle)} {}
diff --git a/src/process.cpp b/src/process.cpp
index 5887b05..508f9e1 100644
--- a/src/process.cpp
+++ b/src/process.cpp
@@ -13,6 +13,7 @@
 #include <windows.h>
 
 #include <cstring>
+#include <stdexcept>
 #include <utility>
 #include <vector>
 
@@ -79,12 +80,11 @@ Process Process::create(const CommandLine& cmd_line, IO io) {
     return Process{create_process(cmd_line, io)};
 }
 
-void Process::wait() {
+void Process::wait() const {
     const auto ret = ::WaitForSingleObject(static_cast<HANDLE>(m_handle), INFINITE);
 
     switch (ret) {
         case WAIT_OBJECT_0:
-            m_handle.close();
             return;
         case WAIT_FAILED:
             throw error::windows(GetLastError(), "WaitForSingleObject");
@@ -94,4 +94,20 @@ void Process::wait() {
     }
 }
 
+int Process::get_exit_code() const {
+    DWORD ec = 0;
+
+    const auto ret = ::GetExitCodeProcess(static_cast<HANDLE>(m_handle), &ec);
+
+    if (!ret) {
+        throw error::windows(GetLastError(), "GetExitCodeProcess");
+    }
+
+    if (ec == STILL_ACTIVE) {
+        throw std::runtime_error{"Attempted to query the exit code of a running process"};
+    }
+
+    return static_cast<int>(ec);
+}
+
 } // namespace winapi
-- 
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