# HG changeset patch
# User Sebastien Jodogne <s.jodogne@gmail.com>
# Date 1792681565 -7200
# Node ID 9f5e962f174e7b9f4f8c503628f861f482180d31
# Parent  5bfcb432ad3d46037323ed48b48bd140ae2c472c
clarified DCMTK_MAX_SEQUENCE_NESTING explanation

diff -r 5bfcb432ad3d -r 9f5e962f174e OrthancFramework/Resources/CMake/DcmtkConfigurationStatic-3.7.1.cmake
--- a/OrthancFramework/Resources/CMake/DcmtkConfigurationStatic-3.7.1.cmake	Thu Oct 22 16:25:27 2026 +0200
+++ b/OrthancFramework/Resources/CMake/DcmtkConfigurationStatic-3.7.1.cmake	Thu Oct 22 17:06:05 2026 +0200
@@ -322,13 +322,25 @@
 
 # 2026-10-22: On several GNU/Linux distributions (notably Ubuntu
 # 22.04), Orthanc was observed to crash when using the system-wide
-# civetweb library and allowing DCMTK to process sequences nested up
-# to 37 levels deep. This issue can be reproduced using the DICOM
-# sample file
-# "orthanc-tests/Database/2026-05-06-Deeply-Nested-Sequence.dcm". The
-# issue does not occur when civetweb is statically linked by setting
-# "-DUSE_SYSTEM_CIVETWEB=OFF". The exact cause for this difference is
-# unknown, but it appears to be related to stack management across
-# shared libraries. We therefore limit the maximum nesting depth to 32
-# levels.
+# civetweb library and allowing DCMTK to process sequences nested
+# deeper than 37 levels. This issue can be reproduced by uploading the
+# DICOM sample file
+# "orthanc-tests/Database/2026-05-06-Deeply-Nested-Sequence.dcm" using
+# the REST API of Orthanc.
+#
+# The issue does not occur when civetweb is statically linked by
+# setting "-DUSE_SYSTEM_CIVETWEB=OFF". This is because the system-wide
+# civetweb shared library is built by setting the CMake option
+# "CIVETWEB_THREAD_STACK_SIZE" to its default value (102400), which in
+# turn defines the macro "USE_STACK_SIZE", which finally lead to a
+# call to "pthread_attr_setstacksize()". If the macro "USE_STACK_SIZE"
+# is not defined (which is the case with "-DUSE_SYSTEM_CIVETWEB=OFF"),
+# "pthread_attr_setstacksize()" is not called and the civetweb workers
+# use the default stack size of the OS, which happens to be sufficient
+# to handle "2026-05-06-Deeply-Nested-Sequence.dcm".
+#
+# We therefore limit the maximum nesting depth to 32 levels to ensure
+# consistency between system-wide and static versions of civetweb.
+#
+# For reference: https://github.com/civetweb/civetweb/pull/1398
 add_definitions(-DDCMTK_MAX_SEQUENCE_NESTING=32)