From 27fbf9fc89b8474547b8d6a4757dff701314c6ef Mon Sep 17 00:00:00 2001
From: Paul Dreik <rdfind@pauldreik.se>
Date: Sat, 21 Feb 2026 17:49:00 +0100
Subject: [PATCH 1/2] #128 ensure results file is readable before iterating
 over files

---
 Rdutil.cc |  6 ++++++
 Rdutil.hh |  7 +++++++
 rdfind.cc | 11 +++++++++++
 3 files changed, 24 insertions(+)

diff --git a/Rdutil.cc b/Rdutil.cc
index 4142ffe..6f52e8e 100644
--- a/Rdutil.cc
+++ b/Rdutil.cc
@@ -27,6 +27,12 @@
 // class declaration
 #include "Rdutil.hh"
 
+bool
+Rdutil::trywritetofile(const std::string& filename)
+{
+  return !!std::ofstream(filename);
+}
+
 int
 Rdutil::printtofile(const std::string& filename) const
 {
diff --git a/Rdutil.hh b/Rdutil.hh
index 2bd629f..11e73c3 100644
--- a/Rdutil.hh
+++ b/Rdutil.hh
@@ -24,6 +24,13 @@ public:
   {
   }
 
+  /**
+   * opens the given file for writing and closes it again.
+   * @param filename
+   * @return true if it went ok
+   */
+  static bool trywritetofile(const std::string& filename);
+
   /**
    * print file names to a file, with extra information.
    * @param filename
diff --git a/rdfind.cc b/rdfind.cc
index c64ad42..d37fae6 100644
--- a/rdfind.cc
+++ b/rdfind.cc
@@ -91,6 +91,17 @@ main(int narg, const char* argv[])
   global_options = &o;
   dirlist.setcallbackfcn(&report);
 
+  if (o.makeresultsfile) {
+    // make sure the results file can be opened, before doing all potentially
+    // lengthy work. in case of permission problems, it is not fun to find out
+    // only after the fact. see https://github.com/pauldreik/rdfind/issues/128
+    if (!Rdutil::trywritetofile(o.resultsfile)) {
+      std::cerr << "could not write to results file \"" << o.resultsfile
+                << "\"\n";
+      std::exit(EXIT_FAILURE);
+    }
+  }
+
   // now loop over path list and add the files
 
   // done with arguments. start parsing files and directories!

From 1481838bf363e3f7f2b5f5b66b642ae1c88ebd9a Mon Sep 17 00:00:00 2001
From: Paul Dreik <rdfind@pauldreik.se>
Date: Sat, 21 Feb 2026 17:49:17 +0100
Subject: [PATCH 2/2] simplify results file opening

---
 Rdutil.cc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Rdutil.cc b/Rdutil.cc
index 6f52e8e..bc2d181 100644
--- a/Rdutil.cc
+++ b/Rdutil.cc
@@ -37,8 +37,7 @@ int
 Rdutil::printtofile(const std::string& filename) const
 {
   // open a file to print to
-  std::ofstream f1;
-  f1.open(filename.c_str(), std::ios_base::out);
+  std::ofstream f1(filename);
   if (!f1.is_open()) {
     std::cerr << "could not open file \"" << filename << "\"\n";
     return -1;