diff --git a/README.md b/README.md
index 7bdf9fd7..1a03739f 100644
--- a/README.md
+++ b/README.md
@@ -5901,7 +5901,7 @@ Return a constant string constructed based on the printf-liked formated string
 and its arguments.
 
 The string is constructed at run time and uses a temporary space on the stack.
-If the constructed string is longer than M\_USE\_CSTR\_ALLOC (default 256),
+If the constructed string is longer than M\_USE\_CSTR\_ALLOC-1,
 the string is truncated. Example:
 
         strcmp( M_CSTR("Len=%d", 17) , "Len=17" ) == 0
@@ -6503,13 +6503,13 @@ The full C definition are:
            that needs multiple calls (array, map, ...)
            It is common to all calls to the same object */
         typedef struct m_serial_local_s {
-         m_serial_ll_t data[M_SERIAL_MAX_DATA_SIZE];
+         m_serial_ll_t data[M_USE_SERIAL_MAX_DATA_SIZE];
         } m_serial_local_t[1];
         
         // Object to handle the generic serial read of an object.
         typedef struct m_serial_read_s {
          const struct m_serial_read_interface_s *m_interface;
-         m_serial_ll_t data[M_SERIAL_MAX_DATA_SIZE];
+         m_serial_ll_t data[M_USE_SERIAL_MAX_DATA_SIZE];
         } m_serial_read_t[1];
         
         // Interface exported by the serial read object.
@@ -6533,7 +6533,7 @@ The full C definition are:
         // Object to handle the generic serial write of an object.
         typedef struct m_serial_write_s {
          const struct m_serial_write_interface_s *m_interface;
-         m_serial_ll_t data[M_SERIAL_MAX_DATA_SIZE];
+         m_serial_ll_t data[M_USE_SERIAL_MAX_DATA_SIZE];
         } m_serial_write_t[1];
         
         // Interface exported by the serial write object.
@@ -6714,14 +6714,6 @@ Thread Local Storage variables have to be reinitialized properly
 with the reset function. This may result in subtle difference between the
 serial code and the parallel code.
 
-#### Global Conditional Code
-
-##### M\_USE\_WORKER
-
-This macro indicates if the multi-thread code shall be used (=1) or not (=0).
-It can be overloaded by the user code before including any headers of M\*LIB.
-If it is not defined, the default is to use the multi-thread code.
-
 #### methods
 
 The following methods are available:
@@ -7524,6 +7516,134 @@ otherwise the behavior of the object is undefined.
 Clear the serialization object 'serial'.
 
 
+# Global User Customization
+
+The behavior of M\*LIB can be customized globally by defining the following macros
+before including any headers of M\*LIB.
+If a macro is not defined before including any M\*LIB header,
+the default value will be used.
+
+Theses macros shall not be defined after including any M\*LIB header.
+
+## M\_USE\_UNDEF\_ATOMIC
+
+Undefine the macro _Atomic in m-atomic.h if stdatomic.h is included.
+It is needed on MSYS2 due to a bug in their headers which is not fixed yet. 
+
+Default value: 1 (undef) on MSYS2, 0 otherwise.
+
+## M\_USE\_STDIO
+
+This macro indicates if the system header stdio.h shall be included
+and the FILE functions be defined (=1) or not (=0).
+
+Default value: 1
+
+## M\_USE\_STDARG
+
+This macro indicates if the system header stdarg.h shall be included
+and the va\_args functions be defined (=1) or not (=0).
+
+Default value: 1 (true)
+
+## M\_USE\_CSTR\_ALLOC
+
+Define the allocation size of the temporary strings created by M\_CSTR
+(including the final nul char).
+
+Default value: 256.
+
+## M\_USE\_IDENTIFIER\_ALLOC
+
+Define the allocation size of a C identifier in the source code
+(excluding the final nul char).
+It is used to represent a C identifier by a C string.
+
+Default value: 128
+
+## M\_USE\_THREAD\_BACKEND
+
+Define the thread backend to use by m-mutex.h:
+
+* 1: for C11 header threads.h
+* 2: for WINDOWS header windows.h
+* 3: for POSIX THREAD header pthread.h
+
+Default value: autodetect in function of the running system.
+
+## M\_USE\_WORKER
+
+This macro indicates if the multi-thread code of m-worker.h shall be used (=1) or not (=0)
+- In this case, a single-thread code is used -.
+
+Default value: 1
+
+## M\_USE\_WORKER\_CLANG\_BLOCK
+
+This macro indicates if the workers shall use the CLANG block extension (=1) or not (=0).
+
+Default value: 1 (on clang), 0 (otherwise)
+
+## M\_USE\_WORKER\_CPP\_FUNCTION
+
+This macro indicates if the workers shall use the C++ lambda function (=1) or not (=0).
+
+Default value: 1 (compiled in C++), 0 (otherwise)
+
+## M\_USE\_BACKOFF\_MAX\_COUNT
+
+Define the maximum iteration of the backoff exponential scheme
+for the synchronization waiting loop of multithreading code.
+
+Default value: 6
+
+## M\_USE\_SERIAL\_MAX\_DATA\_SIZE
+
+Define the size of the private data (reserved to the serial implementation) in a serial object
+(as a number of pointers or equivalent objects).
+
+Default value: 4
+
+## M\_USE\_MEMPOOL\_MAX\_PER\_SEGMENT(type)
+
+Define the number of elements to allocate in a segment per object of type 'type'.
+
+Default value: number of elements that fits in a 16KB page.
+
+## M\_USE\_DEQUE\_DEFAULT\_SIZE
+
+Define the default size of a segment for a deque structure.
+
+Default value: 8 elements.
+
+## M\_MEMORY\_ALLOC
+
+See [m-core.h](#m-core)
+
+## M\_MEMORY\_REALLOC
+
+See [m-core.h](#m-core)
+
+## M\_MEMORY\_FULL
+
+See [m-core.h](#m-core)
+
+## M\_ASSERT
+
+See [m-core.h](#m-core)
+
+## M\_ASSERT\_SLOW
+
+See [m-core.h](#m-core)
+
+## M\_ASSERT\_INIT
+
+See [m-core.h](#m-core)
+
+## M\_ASSERT\_INDEX
+
+See [m-core.h](#m-core)
+
 
 # License