diff --git a/libisoburn/libisoburn.ver b/libisoburn/libisoburn.ver
index afc554a9..176ee8df 100644
--- a/libisoburn/libisoburn.ver
+++ b/libisoburn/libisoburn.ver
@@ -124,6 +124,7 @@ Xorriso_destroy;
 Xorriso_dialog;
 Xorriso_eval_problem_status;
 Xorriso_execute_option;
+Xorriso_fetch_outlists;
 Xorriso_get_problem_status;
 Xorriso_interpreter;
 Xorriso_lst_destroy_all;
diff --git a/xorriso/base_obj.c b/xorriso/base_obj.c
index 85c4923c..963563a9 100644
--- a/xorriso/base_obj.c
+++ b/xorriso/base_obj.c
@@ -25,6 +25,7 @@
 #include <sys/time.h>
 #include <time.h>
 #include <errno.h>
+#include <pthread.h>
 
 #ifdef HAVE_STDINT_H
 #include <stdint.h>
@@ -317,6 +318,8 @@ int Xorriso_new(struct XorrisO ** xorriso,char *progname, int flag)
    m->info_msglists[i]= NULL;
    m->msglist_flags[i]= 0;
  }
+ m->lib_msg_queue_lock_ini= 0;
+ m->result_msglists_lock_ini= 0;
  m->msglist_stackfill= 0;
  m->status_history_max= Xorriso_status_history_maX;
  m->scsi_log= 0;
@@ -433,6 +436,14 @@ int Xorriso_new(struct XorrisO ** xorriso,char *progname, int flag)
  if(ret <= 0)
    goto failure;
  Xorriso_preparer_string(m, m->preparer_id, 1); /* avoids library calls */
+ ret= pthread_mutex_init(&(m->lib_msg_queue_lock), NULL);
+ if(ret != 0)
+   goto failure;
+ m->lib_msg_queue_lock_ini= 1;
+ ret= pthread_mutex_init(&(m->result_msglists_lock), NULL);
+ if(ret != 0)
+   goto failure;
+ m->result_msglists_lock_ini= 1;
 
  if(leafname != NULL)
    free(leafname);
@@ -513,7 +524,11 @@ int Xorriso_destroy(struct XorrisO **xorriso, int flag)
  for(i= 0; i < Xorriso_max_appended_partitionS; i++)
    if(m->appended_partitions[i] != NULL)
      free(m->appended_partitions[i]);
-
+ if(m->lib_msg_queue_lock_ini)
+   pthread_mutex_destroy(&(m->lib_msg_queue_lock));
+ if(m->result_msglists_lock_ini)
+   pthread_mutex_destroy(&(m->result_msglists_lock));
+ 
  Xorriso_detach_libraries(m, flag&1);
 
  free((char *) m);
diff --git a/xorriso/lib_mgt.c b/xorriso/lib_mgt.c
index b302645a..669d1dfd 100644
--- a/xorriso/lib_mgt.c
+++ b/xorriso/lib_mgt.c
@@ -23,6 +23,7 @@
 #include <sys/time.h>
 #include <time.h>
 #include <errno.h>
+#include <pthread.h>
 
 #ifdef HAVE_STDINT_H
 #include <stdint.h>
@@ -469,15 +470,26 @@ cannot:;
 int Xorriso_process_msg_queues(struct XorrisO *xorriso, int flag)
 {
  int ret, error_code= 0, os_errno= 0, count= 0, pass, imgid, tunneled;
- int name_prefix_code;
+ int name_prefix_code, locked= 0, uret;
  char severity[80];
 
 #ifdef Xorriso_with_libjtE
  char *msg;
 #endif
 
- if(!xorriso->libs_are_started)
-   return(1);
+ if(!xorriso->libs_are_started) {
+   ret= 1; goto ex;
+ }
+
+ ret= pthread_mutex_lock(&(xorriso->lib_msg_queue_lock));
+ if(ret != 0) {
+   Xorriso_msgs_submit(xorriso, 0,
+              "Cannot aquire mutex lock for processing library message queues",
+               errno, "FATAL", 0);
+   ret= -1; goto ex;
+ }
+ locked= 1;
+
  for(pass= 0; pass< 3; pass++) {
    while(1) {
      tunneled= 0;
@@ -536,6 +548,17 @@ int Xorriso_process_msg_queues(struct XorrisO *xorriso, int flag)
            count);
    Xorriso_info(xorriso, 0);
  }
+ ret= 1;
+ex:;
+ if(locked) {
+   uret= pthread_mutex_unlock(&(xorriso->lib_msg_queue_lock));
+   if(uret != 0) {
+     Xorriso_msgs_submit(xorriso, 0,
+             "Cannot release mutex lock for processing library message queues",
+              errno, "FATAL", 0);
+     ret= -1;
+   }
+ }
  return(1);
 }
 
diff --git a/xorriso/text_io.c b/xorriso/text_io.c
index f8aff6bb..acc37c3b 100644
--- a/xorriso/text_io.c
+++ b/xorriso/text_io.c
@@ -23,6 +23,8 @@
 #include <time.h>
 #include <errno.h>
 #include <signal.h>
+#include <pthread.h>
+
 
 /* for -charset */
 #include <iconv.h>
@@ -520,6 +522,68 @@ ex:;
 }
 
 
+static int Xorriso_lock_outlists(struct XorrisO *xorriso, int flag)
+{
+ int ret;
+ static int complaints= 0, complaint_limit= 5; 
+
+ ret= pthread_mutex_lock(&(xorriso->result_msglists_lock));
+ if(ret != 0) {
+   /* Cannot report failure through the failing message output system */
+   complaints++;
+   if(complaints < complaint_limit)
+     fprintf(stderr,
+             "xorriso : pthread_mutex_lock() for outlists returns %d\n",
+             ret);
+   return(-1);
+ }
+ return(1);
+}
+
+
+static int Xorriso_unlock_outlists(struct XorrisO *xorriso, int flag)
+{
+ int ret;
+ static int complaints= 0, complaint_limit= 5; 
+
+ ret= pthread_mutex_unlock(&(xorriso->result_msglists_lock));
+ if(ret != 0) {
+   /* Cannot report failure through the failing message output system */
+   complaints++;
+   if(complaints < complaint_limit)
+     fprintf(stderr,
+             "xorriso : pthread_mutex_unlock() for outlists returns %d\n",
+             ret);
+   return(0);
+ }
+ return(1);
+}
+
+
+static int Xorriso_write_to_msglist(struct XorrisO *xorriso,
+                                    struct Xorriso_lsT **xorriso_msglist,
+                                    char *text, int flag)
+{
+ int ret;
+ struct Xorriso_lsT *msglist;
+
+ ret= Xorriso_lock_outlists(xorriso, 0);
+ if(ret <= 0)
+   return(-1);
+ msglist= *xorriso_msglist;
+ ret= Xorriso_lst_append_binary(&msglist, text, strlen(text) + 1, 0);
+ if(ret <= 0) {
+   ret= -1; goto ex;
+ }
+ if(*xorriso_msglist == NULL)
+   *xorriso_msglist= msglist;
+ ret= 1;
+ex:;
+ Xorriso_unlock_outlists(xorriso, 0);
+ return(ret);
+}
+
+
 int Xorriso_write_to_channel(struct XorrisO *xorriso,
                              char *in_text, int channel_no, int flag)
 /*
@@ -534,7 +598,6 @@ bit15= with bit1 to bit3: close depicted log file
  int ret= 1, info_redirected= 0, result_redirected= 0;
  char prefix[16];
  FILE *logfile_fp, *pktlog_fp;
- struct Xorriso_lsT *msglist;
  static int num_channels= 4;
  static char channel_prefixes[4][4]= {".","R","I","M"};
 
@@ -610,22 +673,20 @@ bit15= with bit1 to bit3: close depicted log file
  }
  if(result_redirected) {
    if(channel_no==1 || channel_no==3) {
-     msglist= xorriso->result_msglists[xorriso->msglist_stackfill - 1];
-     ret= Xorriso_lst_append_binary(&msglist, text, strlen(text) + 1, 0);
+     ret= Xorriso_write_to_msglist(xorriso,
+               &(xorriso->result_msglists[xorriso->msglist_stackfill - 1]),
+               text, 0);
      if(ret <= 0)
-       {ret= -1; goto ex;}
-     if(xorriso->result_msglists[xorriso->msglist_stackfill - 1] == NULL)
-       xorriso->result_msglists[xorriso->msglist_stackfill - 1]= msglist;
+       { ret= -1; goto ex; }
    }
  }
  if(info_redirected) {
    if(channel_no==2 || channel_no==3) {
-     msglist= xorriso->info_msglists[xorriso->msglist_stackfill - 1];
-     ret= Xorriso_lst_append_binary(&msglist, text, strlen(text) + 1, 0);
+     ret= Xorriso_write_to_msglist(xorriso,
+               &(xorriso->info_msglists[xorriso->msglist_stackfill - 1]),
+               text, 0);
      if(ret <= 0)
-       {ret= -1; goto ex;}
-     if(xorriso->info_msglists[xorriso->msglist_stackfill - 1] == NULL)
-       xorriso->info_msglists[xorriso->msglist_stackfill - 1]= msglist;
+       { ret= -1; goto ex; }
    }
  }
  if((channel_no == 1 && result_redirected) ||
@@ -718,10 +779,17 @@ ex:
 int Xorriso_push_outlists(struct XorrisO *xorriso, int *stack_handle,
                           int flag)
 {
+ int ret, locked= 0;
+
+ ret= Xorriso_lock_outlists(xorriso, 0);
+ if(ret != 0)
+   {ret= -1; goto ex;}
+ locked= 1;
+
  if(xorriso->msglist_stackfill + 1 >= Xorriso_max_outlist_stacK) {
    Xorriso_msgs_submit(xorriso, 0,
                 "Overflow of message output redirection stack", 0, "FATAL", 0);
-   return(-1);
+   ret= -1; goto ex;
  }
  if((flag & 3) == 0)
    flag|= 3;
@@ -730,21 +798,74 @@ int Xorriso_push_outlists(struct XorrisO *xorriso, int *stack_handle,
  xorriso->info_msglists[xorriso->msglist_stackfill - 1]= NULL;
  xorriso->msglist_flags[xorriso->msglist_stackfill - 1]= flag & 3;
  *stack_handle= xorriso->msglist_stackfill - 1;
+ ret= 1;
+ex:;
+ if(locked)
+   Xorriso_unlock_outlists(xorriso, 0);
+ return(ret);
  return(1);
 }
 
 
+int Xorriso_fetch_outlists(struct XorrisO *xorriso, int stack_handle,
+                           struct Xorriso_lsT **result_list,
+                           struct Xorriso_lsT **info_list, int flag)
+{
+ int ret, locked= 0;
+
+ ret= Xorriso_process_msg_queues(xorriso, 0);
+ if(ret <= 0)
+   goto ex;
+ if((flag & 3) == 0)
+   flag|= 3;
+
+ ret= Xorriso_lock_outlists(xorriso, 0);
+ if(ret != 0)
+   {ret= -1; goto ex;}
+ locked= 1;
+
+ if(stack_handle == -1)
+   stack_handle= xorriso->msglist_stackfill - 1;
+ if(stack_handle < 0 || stack_handle >= xorriso->msglist_stackfill) {
+   Xorriso_msgs_submit(xorriso, 0,
+                "Program error: Wrong message output redirection stack handle",
+                0, "FATAL", 0);
+   ret= -1; goto ex;
+ }
+
+ if(flag & 1) {
+   *result_list= xorriso->result_msglists[stack_handle];
+   xorriso->result_msglists[stack_handle]= NULL;
+ }
+ if(flag & 2) {
+   *info_list= xorriso->info_msglists[stack_handle];
+   xorriso->info_msglists[stack_handle]= NULL;
+ }
+
+ ret= 1;
+ex:;
+ if(locked)
+   Xorriso_unlock_outlists(xorriso, 0);
+ return(ret);
+}
+
+
 int Xorriso_pull_outlists(struct XorrisO *xorriso, int stack_handle,
                           struct Xorriso_lsT **result_list,
                           struct Xorriso_lsT **info_list, int flag)
 {
- int i;
+ int i, ret, locked= 0;
+
+ ret= Xorriso_lock_outlists(xorriso, 0);
+ if(ret != 0)
+   {ret= -1; goto ex;}
+ locked= 1;
 
  if(stack_handle < 0 || stack_handle >= xorriso->msglist_stackfill) {
    Xorriso_msgs_submit(xorriso, 0,
                 "Program error: Wrong message output redirection stack handle",
                 0, "FATAL", 0);
-   return(-1);
+   ret= -1; goto ex;
  }
  *result_list= xorriso->result_msglists[stack_handle];
  *info_list= xorriso->info_msglists[stack_handle];
@@ -753,7 +874,11 @@ int Xorriso_pull_outlists(struct XorrisO *xorriso, int stack_handle,
    xorriso->info_msglists[i - 1]= xorriso->info_msglists[i];
  }
  xorriso->msglist_stackfill--;
- return(1);
+ ret= 1;
+ex:;
+ if(locked)
+   Xorriso_unlock_outlists(xorriso, 0);
+ return(ret);
 }
 
 
@@ -972,26 +1097,12 @@ int Xorriso_msgs_submit(struct XorrisO *xorriso,
    xorriso->info_text[li+lt]= '\n';
  xorriso->info_text[li+lt+1]= 0;
 
-#ifdef NIX
-
- /* <<< */
- Xorriso_info(xorriso,4|(flag&3));
- if(os_errno>0) {
-   sprintf(xorriso->info_text, "%s%s : %s\n",
-           pfx_list[(flag>>2)&15], sev_text, strerror(os_errno));
-   Xorriso_info(xorriso,4|(flag&3));
- }
-
-#else
-
  if(os_errno>0) {
    sprintf(xorriso->info_text + strlen(xorriso->info_text) - 1,
            " : %s\n", strerror(os_errno));
  }
  Xorriso_info(xorriso,4|(flag&3));
 
-#endif
-
  return(1);   
 }
 
diff --git a/xorriso/xorriso.h b/xorriso/xorriso.h
index bedabf77..b93ea6a7 100644
--- a/xorriso/xorriso.h
+++ b/xorriso/xorriso.h
@@ -27,6 +27,13 @@
      @since major.minor.micro
    If this mark is missing, then the feature was present before release 0.5.8.
 
+   Please note that struct XorrisO and its API calls are _not_ thread-safe in
+   general. It is not permissible to run two API calls on the same
+   XorrisO object concurrently.
+   The only exception is
+     Xorriso_fetch_outlists()
+   in order to learn about the ongoing text output of other API calls.
+
 
    There is a lower level of API which consists of libisofs.h, libburn.h and
    libisoburn.h. One should not mix those calls with the ones of xorriso.h .
@@ -585,6 +592,37 @@ int Xorriso_push_outlists(struct XorrisO *xorriso, int *stack_handle,
                           int flag);
 
 
+/** Obtain the currently collected text messages of redirected info and
+    result channel. 
+    The messages are handed out as two lists. Both lists have to be disposed
+    via Xorriso_lst_destroy_all() when they are no longer needed.
+    The message lists are either NULL or represented by their first
+    Xorriso_lsT item.
+
+    This call is safe for being used by a concurrent thread while a
+    xorriso API call is being executed on the same struct XorrisO.
+    In such a situation, it should not be used with high frequency in order
+    not to hamper the ongoing xorriso operation by blocking its message
+    output facility. Ten times per second should be enough.
+
+    @since 1.2.6
+    @param xorriso       The environment handle
+    @param stack_handle  An id number returned by Xorriso_push_outlists()
+                         and not yet revoked by Xorriso_pull_outlists().
+                         Submit -1 to address the most recent valid id.
+    @param result_list   Result and mark messages (usually directed to stdout)
+    @param info_list     Info and mark messages (usually directed to stderr)
+    @param flag          Bitfield for control purposes
+                          bit0= fetch result channel
+                          bit1= fetch info channel
+                         If bit0 and bit1 are 0, both channels get fetched.
+    @return              1 on success, <=0 if failure
+*/
+int Xorriso_fetch_outlists(struct XorrisO *xorriso, int stack_handle,
+                           struct Xorriso_lsT **result_list,
+                           struct Xorriso_lsT **info_list, int flag);
+
+
 /** Disable the redirection given by stack_handle. If it was the current
     receiver of messages then switch output to the next older redirection
     resp. to the normal channels if no redirections are stacked any more.
@@ -594,7 +632,9 @@ int Xorriso_push_outlists(struct XorrisO *xorriso, int *stack_handle,
     The message lists are either NULL or represented by their first
     Xorriso_lsT item.
     @param xorriso       The environment handle
-    @param stack_handle  The id number returned by Xorriso_push_outlists()
+    @param stack_handle  An id number returned by Xorriso_push_outlists()
+                         and not yet revoked by Xorriso_pull_outlists().
+                         This handle is invalid after the call.
     @param result_list   Result and mark messages (usually directed to stdout)
     @param info_list     Info and mark messages (usually directed to stderr)
     @param flag          unused yet, submit 0
diff --git a/xorriso/xorriso_private.h b/xorriso/xorriso_private.h
index e5d499d3..84adab58 100644
--- a/xorriso/xorriso_private.h
+++ b/xorriso/xorriso_private.h
@@ -561,6 +561,11 @@ struct XorrisO { /* the global context of xorriso */
                                                */
  int msglist_stackfill;
 
+ int lib_msg_queue_lock_ini;
+ int result_msglists_lock_ini;
+ pthread_mutex_t lib_msg_queue_lock;
+ pthread_mutex_t result_msglists_lock;
+
  int status_history_max; /* for -status long_history */
  
  /* 0= no logging of SCSI commands, 1= to stderr */
diff --git a/xorriso/xorriso_timestamp.h b/xorriso/xorriso_timestamp.h
index f7aff236..dd2db044 100644
--- a/xorriso/xorriso_timestamp.h
+++ b/xorriso/xorriso_timestamp.h
@@ -1 +1 @@
-#define Xorriso_timestamP "2012.09.09.181723"
+#define Xorriso_timestamP "2012.09.11.092703"