From f45ae6a4d858e2cf0cf1f26c50eb62138287dc19 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 20 Nov 2009 10:27:43 +0000
Subject: [PATCH] From David Fries, "I was trying to create a lot of threads
 under 32 bit Linux, but could only create 376, then the program would hang.
 376 * 8MB stack per thread = 3008 MB The stack size allocated per thread blew
 the process address stack. To get more threads you have to specify a smaller
 per thread stack, but while the Thread::start says it will limit the stack
 size to the smallest allowable stack size, it won't let it be smaller than
 the default.  I included the limits.h header to use PTHREAD_STACK_MIN as the
 minimum stack size.

As for the deadlock, if the pthread_create failed, the new thread
doesn't exist and doesn't call threadStartedBlock.release(), so the
existing thread deadlocks on threadStartedBlock.block().  Only block
if the thread was started."
---
 include/osgDB/Output                 |  2 ++
 src/OpenThreads/pthreads/PThread.c++ | 45 +++++++++++++---------------
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/include/osgDB/Output b/include/osgDB/Output
index 1efedcdb7..24264c96e 100644
--- a/include/osgDB/Output
+++ b/include/osgDB/Output
@@ -91,9 +91,11 @@ class OSGDB_EXPORT Output : public osgDB::ofstream
         virtual std::string getFileNameForOutput(const std::string& filename) const;
         const std::string& getFileName() const { return _filename; }
 
+        // Set and get if export texture files during write
         void setOutputTextureFiles(bool flag) { _outputTextureFiles = flag; }
         bool getOutputTextureFiles() const { return _outputTextureFiles; }
 
+        // support code for OutputTextureFiles
         virtual std::string getTextureFileNameForOutput();
 
         void setOutputShaderFiles(bool flag) { _outputShaderFiles = flag; }
diff --git a/src/OpenThreads/pthreads/PThread.c++ b/src/OpenThreads/pthreads/PThread.c++
index db0b864b5..0f46a138d 100644
--- a/src/OpenThreads/pthreads/PThread.c++
+++ b/src/OpenThreads/pthreads/PThread.c++
@@ -21,6 +21,7 @@
 #include <sys/types.h>
 #include <unistd.h>
 #include <pthread.h>
+#include <limits.h>
 
 #if defined __linux || defined __sun || defined __APPLE__
 #include <string.h>
@@ -588,29 +589,28 @@ int Thread::start() {
 
     PThreadPrivateData *pd = static_cast<PThreadPrivateData *> (_prvData);
 
-    size_t defaultStackSize;
-    pthread_attr_getstacksize( &thread_attr, &defaultStackSize);
-    if(status != 0) {
-    return status;
-    }
-
-    if(defaultStackSize < pd->stackSize) {
-
-    pthread_attr_setstacksize( &thread_attr, pd->stackSize);
-    if(status != 0) {
-        return status;
-    }
+    //-------------------------------------------------------------------------
+    // Set the stack size if requested, but not less than a platform reasonable
+    // value.
+    //
+    if(pd->stackSize) {
+        if(pd->stackSize < PTHREAD_STACK_MIN)
+            pd->stackSize = PTHREAD_STACK_MIN;
+        pthread_attr_setstacksize( &thread_attr, pd->stackSize);
+        if(status != 0) {
+            return status;
+        }
     }
 
     //-------------------------------------------------------------------------
     // Now get what we actually have...
     //
-    pthread_attr_getstacksize( &thread_attr, &defaultStackSize);
+    size_t size;
+    pthread_attr_getstacksize( &thread_attr, &size);
     if(status != 0) {
     return status;
     }
-
-    pd->stackSize = defaultStackSize;
+    pd->stackSize = size;
 
     //-------------------------------------------------------------------------
     // Prohibit the stack size from being changed.
@@ -635,18 +635,15 @@ int Thread::start() {
     status = pthread_create(&(pd->tid), &thread_attr,
                            ThreadPrivateActions::StartThread,
                            static_cast<void *>(this));
-                           
-    // wait till the thread has actually started.
-    pd->threadStartedBlock.block();
 
-    if(status != 0) {
-    return status;
+    if(status == 0) {
+        // wait till the thread has actually started.
+        pd->threadStartedBlock.block();
+
+        pd->idSet = true;
     }
 
-    pd->idSet = true;
-
-    return 0;
-
+    return status;
 }
 
 //-----------------------------------------------------------------------------