fix: prevent unnecessary console windows

fix #376

source/matplot/CMakeLists.txt

@@ -37,6 +37,7 @@ add_library(matplot
         util/handle_types.h
         util/keywords.h
         util/popen.h
+        util/popen.cpp
         util/type_traits.h
         util/world_cities.cpp
         util/world_map_10m.cpp

source/matplot/util/common.cpp

@@ -8,6 +8,7 @@
 #include <iostream>
 #include <matplot/util/colors.h>
 #include <matplot/util/common.h>
+#include <matplot/util/popen.h>
 #include <random>
 #include <regex>
 #include <set>
@@ -25,17 +26,6 @@
 #pragma warning(pop)
 #endif
 
-#ifdef _WIN32
-#include <windows.h>
-#define PCLOSE _pclose
-#define POPEN _popen
-#define FILENO _fileno
-#else
-#define PCLOSE pclose
-#define POPEN popen
-#define FILENO fileno
-#endif
-
 namespace matplot {
     bool iequals(std::string_view str1, std::string_view str2) {
         if (str1.size() != str2.size()) {

source/matplot/util/popen.cpp

@@ -0,0 +1,102 @@
+#include <matplot/util/popen.h>
+
+#ifdef _WIN32
+#include <io.h>
+
+namespace matplot::detail {
+    // Function to create a new process and return a FILE pointer for
+    // input/output. Mimics _popen behaviour, but does not open console windows
+    // in GUI apps
+    FILE *hiddenPopen(const char *command, const char *mode) {
+        SECURITY_ATTRIBUTES saAttr;
+        HANDLE hChildStdinRd, hChildStdinWr, hStdin, hStdout;
+        STARTUPINFO si;
+        PROCESS_INFORMATION pi;
+
+        // Set up security attributes for inheritable handles
+        saAttr.nLength = sizeof(SECURITY_ATTRIBUTES);
+        saAttr.bInheritHandle = TRUE;
+        saAttr.lpSecurityDescriptor = NULL;
+
+        // Create a pipe for the child process's input
+        if (!CreatePipe(&hChildStdinRd, &hChildStdinWr, &saAttr, 0)) {
+            return nullptr;
+        }
+
+        // Ensure the write handle to the pipe is not inherited by child
+        // processes
+        if (!SetHandleInformation(hChildStdinWr, HANDLE_FLAG_INHERIT, 0)) {
+            CloseHandle(hChildStdinRd);
+            return nullptr;
+        }
+
+        // Create a pipe for the child process's output
+        if (!CreatePipe(&hStdin, &hStdout, &saAttr, 0)) {
+            CloseHandle(hChildStdinRd);
+            CloseHandle(hChildStdinWr);
+            return nullptr;
+        }
+
+        // Ensure the read handle to the output pipe is not inherited by child
+        // processes
+        if (!SetHandleInformation(hStdout, HANDLE_FLAG_INHERIT, 0)) {
+            CloseHandle(hChildStdinRd);
+            CloseHandle(hChildStdinWr);
+            CloseHandle(hStdin);
+            return nullptr;
+        }
+
+        // Configure STARTUPINFO structure for the new process
+        ZeroMemory(&si, sizeof(STARTUPINFO));
+        si.cb = sizeof(STARTUPINFO);
+        si.hStdError = hStdout;
+        si.hStdOutput = hStdout;
+        si.hStdInput = hChildStdinRd;
+        si.dwFlags |= STARTF_USESTDHANDLES;
+
+        // Create the child process, while hiding the window
+        if (!CreateProcess(NULL, const_cast<char *>(command), NULL, NULL, TRUE,
+                           CREATE_NO_WINDOW, NULL, NULL, &si, &pi)) {
+            CloseHandle(hChildStdinRd);
+            CloseHandle(hChildStdinWr);
+            CloseHandle(hStdin);
+            CloseHandle(hStdout);
+            return nullptr;
+        }
+
+        // Close unnecessary handles
+        CloseHandle(hChildStdinRd);
+        CloseHandle(hStdout);
+
+        // Create a FILE pointer from the write handle to the child process's
+        // input
+        FILE *file = _fdopen(_open_osfhandle((intptr_t)hChildStdinWr, 0), mode);
+
+        if (file == nullptr) {
+            CloseHandle(hChildStdinWr);
+            CloseHandle(hStdin);
+            CloseHandle(pi.hProcess);
+            CloseHandle(pi.hThread);
+            return nullptr;
+        }
+
+        return file;
+    }
+
+    // Function to close the process and retrieve its exit code
+    int hiddenPclose(FILE *file) {
+        HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
+        fclose(file);
+        DWORD exitCode;
+
+        // Wait for the process to finish and get its exit code
+        if (WaitForSingleObject(hFile, INFINITE) == WAIT_OBJECT_0 &&
+            GetExitCodeProcess(hFile, &exitCode)) {
+            CloseHandle(hFile);
+            return exitCode;
+        } else {
+            return -1; // Failed to get the exit code
+        }
+    }
+} // namespace matplot::detail
+#endif // _WIN32

source/matplot/util/popen.h

@@ -6,9 +6,19 @@
 #define MATPLOTPLUSPLUS_POPEN_H
 
 #ifdef _WIN32
+#include <stdio.h> //needed for FILE type
 #include <windows.h>
-#define PCLOSE _pclose
-#define POPEN _popen
+
+namespace matplot::detail {
+    // in a GUI application, _popen pops up a window. This version does not.
+    FILE *hiddenPopen(const char *command, const char *mode);
+
+    // close the handle opened by hiddenPopen
+    int hiddenPclose(FILE *file);
+} // namespace matplot::detail
+
+#define PCLOSE ::matplot::detail::hiddenPclose
+#define POPEN ::matplot::detail::hiddenPopen
 #define FILENO _fileno
 #else
 #define PCLOSE pclose