diff --git a/integration_test.py b/integration_test.py
index ccef84eb..27528e16 100644
--- a/integration_test.py
+++ b/integration_test.py
@@ -67,7 +67,7 @@ def test_relative_header_2(record_property, tmpdir, with_pragma_once, inv, sourc
     record_property("stderr", stderr)
     if with_pragma_once:
         assert stderr == ''
-        if inv:
+        if inv or not source_relative:
             assert f'#line 8 "{pathlib.PurePath(tmpdir).as_posix()}/test.h"' in stdout
         else:
             assert '#line 8 "test.h"' in stdout
@@ -94,16 +94,17 @@ def test_relative_header_3(record_property, tmpdir, is_sys, inv, source_relative
         assert "missing header: Header not found" in stderr
     else:
         assert stderr == ''
-        if inv:
-            assert f'#line 8 "{pathlib.PurePath(test_subdir).as_posix()}/test.h"' in stdout
-        else:
+        if source_relative and not inv:
             assert '#line 8 "test_subdir/test.h"' in stdout
+        else:
+            assert f'#line 8 "{pathlib.PurePath(test_subdir).as_posix()}/test.h"' in stdout
 
 @pytest.mark.parametrize("use_short_path", (False, True))
 @pytest.mark.parametrize("relative_include_dir", (False, True))
 @pytest.mark.parametrize("is_sys", (False, True))
 @pytest.mark.parametrize("inv", (False, True))
-def test_relative_header_4(record_property, tmpdir, use_short_path, relative_include_dir, is_sys, inv):
+@pytest.mark.parametrize("source_relative", (False, True))
+def test_relative_header_4(record_property, tmpdir, use_short_path, relative_include_dir, is_sys, inv, source_relative):
     test_subdir = os.path.join(tmpdir, "test_subdir")
     os.mkdir(test_subdir)
     header_file, _ = __test_relative_header_create_header(test_subdir)
@@ -112,13 +113,14 @@ def test_relative_header_4(record_property, tmpdir, use_short_path, relative_inc
 
     test_file = __test_relative_header_create_source(tmpdir, header_file, "test.h", is_include2_sys=is_sys, inv=inv)
 
-    args = [format_include_path_arg("test_subdir" if relative_include_dir else test_subdir), test_file]
+    args = [format_include_path_arg("test_subdir" if relative_include_dir else test_subdir), "test.c" if source_relative else test_file]
 
     _, stdout, stderr = simplecpp(args, cwd=tmpdir)
     record_property("stdout", stdout)
     record_property("stderr", stderr)
+
     assert stderr == ''
-    if (use_short_path and not inv) or (relative_include_dir and inv):
+    if (source_relative and use_short_path and not inv) or (relative_include_dir and inv):
         assert '#line 8 "test_subdir/test.h"' in stdout
     else:
         assert f'#line 8 "{pathlib.PurePath(test_subdir).as_posix()}/test.h"' in stdout
@@ -127,7 +129,8 @@ def test_relative_header_4(record_property, tmpdir, use_short_path, relative_inc
 @pytest.mark.parametrize("relative_include_dir", (False, True))
 @pytest.mark.parametrize("is_sys", (False, True))
 @pytest.mark.parametrize("inv", (False, True))
-def test_relative_header_5(record_property, tmpdir, with_pragma_once, relative_include_dir, is_sys, inv): # test relative paths with ..
+@pytest.mark.parametrize("source_relative", (False, True))
+def test_relative_header_5(record_property, tmpdir, with_pragma_once, relative_include_dir, is_sys, inv, source_relative): # test relative paths with ..
     ## in this test, the subdir role is the opposite then the previous - it contains the test.c file, while the parent tmpdir contains the header file
     header_file, double_include_error = __test_relative_header_create_header(tmpdir, with_pragma_once=with_pragma_once)
     if is_sys:
@@ -139,14 +142,14 @@ def test_relative_header_5(record_property, tmpdir, with_pragma_once, relative_i
     os.mkdir(test_subdir)
     test_file = __test_relative_header_create_source(test_subdir, header_file, header_file_second_path, is_include2_sys=is_sys, inv=inv)
 
-    args = ([format_include_path_arg(".." if relative_include_dir else tmpdir)] if is_sys else []) + ["test.c"]
+    args = ([format_include_path_arg(".." if relative_include_dir else tmpdir)] if is_sys else []) + ["test.c" if source_relative else test_file]
 
     _, stdout, stderr = simplecpp(args, cwd=test_subdir)
     record_property("stdout", stdout)
     record_property("stderr", stderr)
     if with_pragma_once:
         assert stderr == ''
-        if (relative_include_dir or not is_sys) and inv:
+        if (relative_include_dir if is_sys else source_relative) and inv:
             assert '#line 8 "../test.h"' in stdout
         else:
             assert f'#line 8 "{pathlib.PurePath(tmpdir).as_posix()}/test.h"' in stdout
@@ -157,7 +160,8 @@ def test_relative_header_5(record_property, tmpdir, with_pragma_once, relative_i
 @pytest.mark.parametrize("relative_include_dir", (False, True))
 @pytest.mark.parametrize("is_sys", (False, True))
 @pytest.mark.parametrize("inv", (False, True))
-def test_relative_header_6(record_property, tmpdir, with_pragma_once, relative_include_dir, is_sys, inv): # test relative paths with .. that is resolved only by an include dir
+@pytest.mark.parametrize("source_relative", (False, True))
+def test_relative_header_6(record_property, tmpdir, with_pragma_once, relative_include_dir, is_sys, inv, source_relative): # test relative paths with .. that is resolved only by an include dir
     ## in this test, both the header and the source file are at the same dir, but there is a dummy inclusion dir as a subdir
     header_file, double_include_error = __test_relative_header_create_header(tmpdir, with_pragma_once=with_pragma_once)
 
@@ -165,7 +169,7 @@ def test_relative_header_6(record_property, tmpdir, with_pragma_once, relative_i
     os.mkdir(test_subdir)
     test_file = __test_relative_header_create_source(tmpdir, header_file, "../test.h", is_include2_sys=is_sys, inv=inv)
 
-    args = [format_include_path_arg("test_subdir" if relative_include_dir else test_subdir), "test.c"]
+    args = [format_include_path_arg("test_subdir" if relative_include_dir else test_subdir), "test.c" if source_relative else test_file]
 
     _, stdout, stderr = simplecpp(args, cwd=tmpdir)
     record_property("stdout", stdout)
diff --git a/simplecpp.cpp b/simplecpp.cpp
index e4f98bb6..599ffdfe 100755
--- a/simplecpp.cpp
+++ b/simplecpp.cpp
@@ -3173,7 +3173,7 @@ static std::string openHeader(std::ifstream &f, const std::string &path)
     return "";
 }
 
-static std::string getRelativeFileName(const std::string &baseFile, const std::string &header)
+static std::string getRelativeFileName(const std::string &baseFile, const std::string &header, bool returnAbsolutePath)
 {
     const std::string baseFileSimplified = simplecpp::simplifyPath(baseFile);
     const std::string baseFileAbsolute = isAbsolutePath(baseFileSimplified) ?
@@ -3185,12 +3185,12 @@ static std::string getRelativeFileName(const std::string &baseFile, const std::s
         headerSimplified :
         simplecpp::simplifyPath(dirPath(baseFileAbsolute) + headerSimplified);
 
-    return extractRelativePathFromAbsolute(path);
+    return returnAbsolutePath ? toAbsolutePath(path) : extractRelativePathFromAbsolute(path);
 }
 
 static std::string openHeaderRelative(std::ifstream &f, const std::string &sourcefile, const std::string &header)
 {
-    return openHeader(f, getRelativeFileName(sourcefile, header));
+    return openHeader(f, getRelativeFileName(sourcefile, header, isAbsolutePath(sourcefile)));
 }
 
 // returns the simplified header path:
@@ -3273,14 +3273,14 @@ static std::string getFileIdPath(const std::map<std::string, simplecpp::TokenLis
     }
 
     if (!systemheader) {
-        const std::string relativeOrAbsoluteFilename = getRelativeFileName(sourcefile, header);// unknown if absolute or relative, but always simplified
-        const std::string match = findPathInMapBothRelativeAndAbsolute(filedata, relativeOrAbsoluteFilename);
+        const std::string relativeFilename = getRelativeFileName(sourcefile, header, true);
+        const std::string match = findPathInMapBothRelativeAndAbsolute(filedata, relativeFilename);
         if (!match.empty()) {
             return match;
         }
         // if the file exists but hasn't been loaded yet then we need to stop searching here or we could get a false match
         std::ifstream f;
-        openHeader(f, relativeOrAbsoluteFilename);
+        openHeader(f, relativeFilename);
         if (f.is_open()) {
             f.close();
             return "";