From bdefb2ab19b8f5bb0a5e638552e7c3cae6b0f8ac Mon Sep 17 00:00:00 2001
From: Joseph Myers This document explains how to port libstdc++-v3 (the GNU C++ library) to
+ This document explains how to port libstdc++-v3 (the GNU C++ library) to
a new target.
- In order to make the GNU C++ library (libstdc++-v3) work with a new
+ In order to make the GNU C++ library (libstdc++-v3) work with a new
target, you must edit some configuration files and provide some new
header files. Unless this is done, libstdc++-v3 will use generic
settings which may not be correct for your target; even if they are
correct, they will likely be inefficient.
- Before you get started, make sure that you have a working C library on
+ Before you get started, make sure that you have a working C library on
your target. The C library need not precisely comply with any
particular standard, but should generally conform to the requirements
imposed by the ANSI/ISO standard.
- In addition, you should try to verify that the C++ compiler generally
+ In addition, you should try to verify that the C++ compiler generally
works. It is difficult to test the C++ compiler without a working
library, but you should at least try some minimal test cases.
- Here are the primary steps required to port the library:
+ Here are the primary steps required to port the library:
- If you are porting to a new operating system (as opposed to a new chip
+ If you are porting to a new operating system (as opposed to a new chip
using an existing operating system), you will need to create a new
directory in the You might have to change the You might have to change the The first file to create in this directory, should be called
+ The first file to create in this directory, should be called
You don't have to provide these definitions if your system library
already defines these types - but the only library known to provide
@@ -95,7 +119,7 @@ provide these macros. Note that this file does not have to include a
header file that defines In addition, several libstdc++-v3 source files unconditionally define
+ In addition, several libstdc++-v3 source files unconditionally define
the macro At this time, there is one libstdc++-v3-specific macro which may be
+ At this time, there is one libstdc++-v3-specific macro which may be
defined. Finally, you should bracket the entire file in an include-guard, like
+ Finally, you should bracket the entire file in an include-guard, like
this:
- We recommend copying an existing We recommend copying an existing If you are porting to a new chip (as opposed to a new operating system
+ If you are porting to a new chip (as opposed to a new operating system
running on an existing chip), you will need to create a new directory in the
We recommend that for a target triplet We recommend that for a target triplet Note that some chip families share a single configuration directory, for
+ Note that some chip families share a single configuration directory, for
example, The The The library requires that you provide three header files to implement
+ The library requires that you provide three header files to implement
character classification, analogous to that provided by the C libraries
The first file to write is The first file to write is The The The The enumeration should give definitions for all the values in the above
+ The enumeration should give definitions for all the values in the above
example, using the values from your native The next file to write is The next file to write is There are two parts of this that you might choose to alter. The first,
and most important, is the line involving Now, you have to write two functions to convert from upper-case to
+ Now, you have to write two functions to convert from upper-case to
lower-case, and vice versa. Here are the IRIX versions:
- Your C library provides equivalents to IRIX's Finally, you have to provide two utility functions that convert strings
+ Finally, you have to provide two utility functions that convert strings
of characters. The versions provided here will always work - but you
could use specialized routines for greater performance if you have
machinery to do that on your system:
- You must also provide the You must also provide the In detail, the functions provided test characters for particular
+ In detail, the functions provided test characters for particular
properties; they are analogous to the functions like The first function is implemented like this on IRIX:
+ The first function is implemented like this on IRIX:
- The The next function is:
+ The next function is:
- This function is similar; it copies the masks for all the characters
from The last two functions again are entirely generic:
+ The last two functions again are entirely generic:
- The C++ library string functionality requires a couple of atomic
+ The C++ library string functionality requires a couple of atomic
operations to provide thread-safety. If you don't take any special
action, the library will use stub versions of these functions that are
not thread-safe. They will work fine, unless your applications are
multi-threaded.
- If you want to provide custom, safe, versions of these functions, there
+ If you want to provide custom, safe, versions of these functions, there
are two distinct approaches. One is to provide a version for your CPU,
using assembly language constructs. The other is to use the
thread-safety primitives in your operating system. In either case, you
make a file called If you are using the assembly-language approach, put this code in
+ If you are using the assembly-language approach, put this code in
If you are using the operating system thread-safety primitives approach,
+ If you are using the operating system thread-safety primitives approach,
you can also put this code in the same CPU directory, in which case no more
work is needed to locate the file. For examples of this approach,
see the Alternatively, if the primitives are more closely related to the OS
+ Alternatively, if the primitives are more closely related to the OS
than they are to the CPU, you can put the With those bits out of the way, you have to actually write
+ With those bits out of the way, you have to actually write
The type is The type is This type must be a signed integral type supporting atomic operations.
If you're using the OS approach, use the same type used by your system's
primitives. Otherwise, use the type for which your CPU provides atomic
primitives.
- Then, you must provide two functions. The bodies of these functions
+ Then, you must provide two functions. The bodies of these functions
must be equivalent to those provided here, but using atomic operations:
- The C++ library requires information about the fundamental data types,
+ The C++ library requires information about the fundamental data types,
such as the minimum and maximum representable values of each type.
You can define each of these values individually, but it is usually
easiest just to indicate how many bits are used in each of the data
types and let the library do the rest. For information about the
macros to define, see the top of If you need to define any macros, you can do so in If you need to define any macros, you can do so in The C++ library is compiled, archived and linked with libtool.
+ The C++ library is compiled, archived and linked with libtool.
Explaining the full workings of libtool is beyond the scope of this
document, but there are a few, particular bits that are necessary for
porting.
- Some parts of the libstdc++-v3 library are compiled with the libtool
+ Some parts of the libstdc++-v3 library are compiled with the libtool
The C++ run-time library contains initialization code that needs to be
+ The C++ run-time library contains initialization code that needs to be
run as the library is loaded. Often, that requires linking in special
object files when the C++ library is built as a shared library, or
taking other system-specific actions.
- The libstdc++-v3 library is linked with the C version of libtool, even
+ The libstdc++-v3 library is linked with the C version of libtool, even
though it is a C++ library. Therefore, the C version of libtool needs to
ensure that the run-time library initializers are run. The usual way to
do this is to build the library using If you need to change how the library is linked, look at
+ If you need to change how the library is linked, look at
Porting libstdc++-v3
+Porting libstdc++-v3
+
-Porting libstdc++-v3
+Porting libstdc++-v3
-
-
Operating system
+Operating system
-config/os
hierarchy. For example, the IRIX
configuration files are all in config/os/irix
. There is no set
@@ -68,7 +92,7 @@ directory. The important information is that there needs to be a
directory under config/os
to store the files for your operating
system.
-configure.target
file to ensure that
+ configure.target
file to ensure that
your new directory is activated. Look for the switch statement that sets
os_include_dir
, and add a pattern to handle your operating system
if the default will not suffice. The switch statement switches on only
@@ -76,17 +100,17 @@ the OS portion of the standard target triplet; e.g., the solaris2.8
in sparc-sun-solaris2.8
. If the new directory is named after the
OS portion of the triplet (the default), then nothing needs to be changed.
-os_defines.h
. This file contains basic macro definitions
that are required to allow the C++ library to work with your C library.
This file should provide macro definitions for __off_t
,
__off64_t
, and __ssize_t
. Typically, this just looks
like:
-#define __off_t off_t
-#define __off64_t off64_t
-#define __ssize_t ssize_t
-
+ #define __off_t off_t
+ #define __off64_t off64_t
+ #define __ssize_t ssize_t
+
off_t
, or the other types; you simply
have to provide the macros.
-_POSIX_SOURCE
. On many systems, defining this macro
causes large portions of the C library header files to be eliminated
at preprocessing time. Therefore, you may have to #undef
this
@@ -110,71 +134,75 @@ need to define. You will need to add them to the
target. It will not work to simply define these macros in
os_defines.h
.
-_G_USING_THUNKS
may be defined to 0 to express that the
port doesn't use thunks (although it is unclear that this is still
useful since libio support isn't currently working and the g++ v3 ABI
invalidates the assumption that some ports don't use thunks).
-#ifndef _GLIBCPP_OS_DEFINES
-#define _GLIBCPP_OS_DEFINES
-...
-#endif
-
+ #ifndef _GLIBCPP_OS_DEFINES
+ #define _GLIBCPP_OS_DEFINES
+ ...
+ #endif
+
-os_defines.h
to use as a
+ os_defines.h
to use as a
starting point.
+
Node:CPU,
-Next:Character types,
-Previous:Operating system,
-Up:Top
+Next:Character types,
+Previous:Operating system,
+Up:Top
+CPU
+CPU
-config/cpu
hierarchy. Much like the Operating system setup,
there are no strict rules on how to organize the CPU configuration
directory, but careful naming choices will allow the configury to find your
setup files without explicit help.
-<CPU>-<vendor>-<OS>
, you
+ <CPU>-<vendor>-<OS>
, you
name your configuration directory config/cpu/<CPU>
. If you do this,
the configury will find the directory itself. Otherwise you will need to
edit the configure.target
file and, in the switch statement that sets
cpu_include_dir
, add a pattern to handle your chip.
-alpha
, alphaev5
, and alphaev6
all use the
config/cpu/alpha
directory, and there is an entry in the
configure.target
switch statement to handle this.
-cpu_include_dir
sets default locations for the files controlling
+ cpu_include_dir
sets default locations for the files controlling
Thread safety and Numeric limits, if the defaults are not
appropriate for your chip.
+
Node:Character types,
-Next:Thread safety,
-Previous:CPU,
-Up:Top
+Next:Thread safety,
+Previous:CPU,
+Up:Top
+Character types
+Character types
-<ctype.h>
header. You can model these on the files provided in
config/os/generic
. However, these files will almost
certainly need some modification.
-ctype_base.h
. This file provides
+ ctype_base.h
. This file provides
some very basic information about character classification. The libstdc++-v3
library assumes that your C library implements <ctype.h>
by using
a table (indexed by character code) containing integers, where each of
@@ -184,33 +212,33 @@ file gives the type of the integer, and the values of the various bit
masks. You will have to peer at your own <ctype.h>
to figure out
how to define the values required by this file.
-ctype_base.h
header file does not need include guards.
+ ctype_base.h
header file does not need include guards.
It should contain a single struct
definition called
ctype_base
. This struct
should contain two type
declarations, and one enumeration declaration, like this example, taken
from the IRIX configuration:
-struct ctype_base
-{
- typedef unsigned int mask;
- typedef int* __to_type;
-
- enum
- {
- space = _ISspace,
- print = _ISprint,
- cntrl = _IScntrl,
- upper = _ISupper,
- lower = _ISlower,
- alpha = _ISalpha,
- digit = _ISdigit,
- punct = _ISpunct,
- xdigit = _ISxdigit,
- alnum = _ISalnum,
- graph = _ISgraph
- };
-};
-
+ struct ctype_base
+ {
+ typedef unsigned int mask;
+ typedef int* __to_type;
+
+ enum
+ {
+ space = _ISspace,
+ print = _ISprint,
+ cntrl = _IScntrl,
+ upper = _ISupper,
+ lower = _ISlower,
+ alpha = _ISalpha,
+ digit = _ISdigit,
+ punct = _ISpunct,
+ xdigit = _ISxdigit,
+ alnum = _ISalnum,
+ graph = _ISgraph
+ };
+ };
+
mask
type is the type of the elements in the table. If your
C library uses a table to map lower-case numbers to upper-case numbers,
@@ -220,29 +248,29 @@ penalty, or if your library doesn't implement toupper
and
tolower
in this way, you can pick any pointer-to-integer type,
but you must still define the type.
-<ctype.h>
. They can
be given symbolically (as above), or numerically, if you prefer. You do
not have to include <ctype.h>
in this header; it will always be
included before ctype_base.h
is included.
-ctype_noninline.h
, which also does
+ ctype_noninline.h
, which also does
not require include guards. This file defines a few member functions
that will be included in include/bits/locale_facets.h
. The first
function that must be written is the ctype<char>::ctype
constructor. Here is the IRIX example:
-ctype<char>::ctype(const mask* __table = 0, bool __del = false,
- size_t __refs = 0)
- : _Ctype_nois<char>(__refs), _M_del(__table != 0 && __del),
- _M_toupper(NULL),
- _M_tolower(NULL),
- _M_ctable(NULL),
- _M_table(!__table
- ? (const mask*) (__libc_attr._ctype_tbl->_class + 1)
- : __table)
- { }
-
+ ctype<char>::ctype(const mask* __table = 0, bool __del = false,
+ size_t __refs = 0)
+ : _Ctype_nois<char>(__refs), _M_del(__table != 0 && __del),
+ _M_toupper(NULL),
+ _M_tolower(NULL),
+ _M_ctable(NULL),
+ _M_table(!__table
+ ? (const mask*) (__libc_attr._ctype_tbl->_class + 1)
+ : __table)
+ { }
+
__libc_attr
. That is
@@ -253,140 +281,142 @@ operating system's tables to map upper-case letters to lower-case, and
vice versa, you should initialize _M_toupper
and
_M_tolower
with those tables, in similar fashion.
-char
-ctype<char>::do_toupper(char __c) const
-{ return _toupper(__c); }
-
-char
-ctype<char>::do_tolower(char __c) const
-{ return _tolower(__c); }
-
+ char
+ ctype<char>::do_toupper(char __c) const
+ { return _toupper(__c); }
+
+ char
+ ctype<char>::do_tolower(char __c) const
+ { return _tolower(__c); }
+
_toupper
and
_tolower
. If you initialized _M_toupper
and
_M_tolower
above, then you could use those tables instead.
-const char*
-ctype<char>::do_toupper(char* __low, const char* __high) const
-{
- while (__low < __high)
- {
- *__low = do_toupper(*__low);
- ++__low;
- }
- return __high;
-}
+
-
- const char*
+ ctype<char>::do_toupper(char* __low, const char* __high) const
+ {
+ while (__low < __high)
+ {
+ *__low = do_toupper(*__low);
+ ++__low;
+ }
+ return __high;
+ }
+
+ const char*
+ ctype<char>::do_tolower(char* __low, const char* __high) const
+ {
+ while (__low < __high)
+ {
+ *__low = do_tolower(*__low);
+ ++__low;
+ }
+ return __high;
+ }
+
-const char*
-ctype<char>::do_tolower(char* __low, const char* __high) const
-{
- while (__low < __high)
- {
- *__low = do_tolower(*__low);
- ++__low;
- }
- return __high;
-}
-ctype_inline.h
file, which
+ ctype_inline.h
file, which
contains a few more functions. On most systems, you can just copy
config/os/generic/ctype_inline.h
and use it on your system.
-isalpha
and
islower
provided by the C library.
-bool
-ctype<char>::
-is(mask __m, char __c) const throw()
-{ return (_M_table)[(unsigned char)(__c)] & __m; }
-
+ bool
+ ctype<char>::
+ is(mask __m, char __c) const throw()
+ { return (_M_table)[(unsigned char)(__c)] & __m; }
+
_M_table
is the table passed in above, in the constructor.
This is the table that contains the bitmasks for each character. The
implementation here should work on all systems.
-const char*
-ctype<char>::
-is(const char* __low, const char* __high, mask* __vec) const throw()
-{
- while (__low < __high)
- *__vec++ = (_M_table)[(unsigned char)(*__low++)];
- return __high;
-}
-
+ const char*
+ ctype<char>::
+ is(const char* __low, const char* __high, mask* __vec) const throw()
+ {
+ while (__low < __high)
+ *__vec++ = (_M_table)[(unsigned char)(*__low++)];
+ return __high;
+ }
+
__low
up until __high
into the vector given by
__vec
.
-const char*
-ctype<char>::
-scan_is(mask __m, const char* __low, const char* __high) const throw()
-{
- while (__low < __high && !this->is(__m, *__low))
- ++__low;
- return __low;
-}
-
-const char*
-ctype<char>::
-scan_not(mask __m, const char* __low, const char* __high) const throw()
-{
- while (__low < __high && this->is(__m, *__low))
- ++__low;
- return __low;
-}
-
+ const char*
+ ctype<char>::
+ scan_is(mask __m, const char* __low, const char* __high) const throw()
+ {
+ while (__low < __high && !this->is(__m, *__low))
+ ++__low;
+ return __low;
+ }
+
+ const char*
+ ctype<char>::
+ scan_not(mask __m, const char* __low, const char* __high) const throw()
+ {
+ while (__low < __high && this->is(__m, *__low))
+ ++__low;
+ return __low;
+ }
+
+
Node:Thread safety,
-Next:Numeric limits,
-Previous:Character types,
-Up:Top
+Next:Numeric limits,
+Previous:Character types,
+Up:Top
+Thread safety
+Thread safety
-atomicity.h
, and the variable
ATOMICITYH
must point to this file.
-config/cpu/<chip>/atomicity.h
, where chip is the name of
your processor (see CPU). No additional changes are necessary to
locate the file in this case; ATOMICITYH
will be set by default.
-atomicity.h
file for IRIX or IA64.
-atomicity.h
file in
the Operating system directory instead. In this case, you must
edit configure.target
, and in the switch statement that handles
@@ -394,120 +424,126 @@ operating systems, override the ATOMICITYH
variable to point to
the appropriate os_include_dir
. For examples of this approach,
see the atomicity.h
file for AIX.
-atomicity.h
itself. This file should be wrapped in an
include guard named _BITS_ATOMICITY_H
. It should define one
type, and two functions.
-_Atomic_word
. Here is the version used on IRIX:
+ _Atomic_word
. Here is the version used on IRIX:
-typedef long _Atomic_word;
-
+ typedef long _Atomic_word;
+
static inline _Atomic_word
-__attribute__ ((__unused__))
-__exchange_and_add (_Atomic_word* __mem, int __val)
-{
- _Atomic_word __result = *__mem;
- *__mem += __val;
- return __result;
-}
-
-static inline void
-__attribute__ ((__unused__))
-__atomic_add (_Atomic_word* __mem, int __val)
-{
- *__mem += __val;
-}
-
+ static inline _Atomic_word
+ __attribute__ ((__unused__))
+ __exchange_and_add (_Atomic_word* __mem, int __val)
+ {
+ _Atomic_word __result = *__mem;
+ *__mem += __val;
+ return __result;
+ }
+
+ static inline void
+ __attribute__ ((__unused__))
+ __atomic_add (_Atomic_word* __mem, int __val)
+ {
+ *__mem += __val;
+ }
+
+
Node:Numeric limits,
-Next:Libtool,
-Previous:Thread safety,
-Up:Top
+Next:Libtool,
+Previous:Thread safety,
+Up:Top
+Numeric limits
+Numeric limits
-include/bits/std_limits.h
.
-os_defines.h
.
+ os_defines.h
.
However, if all operating systems for your CPU are likely to use the
same values, you can provide a CPU-specific file instead so that you
do not have to provide the same definitions for each operating system.
To take that approach, create a new file called cpu_limits.h
in
your CPU configuration directory (see CPU).
+
Node:Libtool,
-Next:GNU Free Documentation License,
-Previous:Numeric limits,
-Up:Top
+Next:GNU Free Documentation License,
+Previous:Numeric limits,
+Up:Top
+Libtool
+Libtool
---tags CXX
option (the C++ definitions for libtool). Therefore,
ltcf-cxx.sh
in the top-level directory needs to have the correct
logic to compile and archive objects equivalent to the C version of libtool,
ltcf-c.sh
. Some libtool targets have definitions for C but not
for C++, or C++ definitions which have not been kept up to date.
-gcc -shared
.
-ltcf-c.sh
in the top-level directory. Find the switch statement
that sets archive_cmds
. Here, adjust the setting for your
operating system.
+GNU Free Documentation License
+GNU Free Documentation License
Copyright © 2000 Free Software Foundation, Inc.
-59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
+
+ Copyright © 2000 Free Software Foundation, Inc.
+ 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
+
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
-Everyone is permitted to copy and distribute verbatim copies
-of this license document, but changing it is not allowed.
-
+
-
The purpose of this License is to make a manual, textbook, or other +
The purpose of this License is to make a manual, textbook, or other written document free in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, @@ -515,12 +551,12 @@ this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. -
This License is a kind of "copyleft", which means that derivative +
This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software. -
We have designed this License in order to use it for manuals for free +
We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; @@ -528,19 +564,19 @@ it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference. -
This License applies to any manual or other work that contains a +
This License applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". -
A "Modified Version" of the Document means any work containing the +
A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language. -
A "Secondary Section" is a named appendix or a front-matter section of +
A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly @@ -551,15 +587,15 @@ connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them. -
The "Invariant Sections" are certain Secondary Sections whose titles +
The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. -
The "Cover Texts" are certain short passages of text that are listed, +
The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. -
A "Transparent" copy of the Document means a machine-readable copy, +
A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, whose contents can be viewed and edited directly and straightforwardly with generic text editors or (for images composed of @@ -571,7 +607,7 @@ format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent. A copy that is not "Transparent" is called "Opaque". -
Examples of suitable formats for Transparent copies include plain +
Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML designed @@ -582,16 +618,16 @@ the DTD and/or processing tools are not generally available, and the machine-generated HTML produced by some word processors for output purposes only. -
The "Title Page" means, for a printed book, the title page itself, +
The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text. -
You may copy and distribute the Document in any medium, either +
You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other @@ -601,12 +637,12 @@ copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3. -
You may also lend copies, under the same conditions stated above, and +
You may also lend copies, under the same conditions stated above, and you may publicly display copies. -
If you publish printed copies of the Document numbering more than 100, +
If you publish printed copies of the Document numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on @@ -618,12 +654,12 @@ Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects. -
If the required texts for either cover are too voluminous to fit +
If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages. -
If you publish or distribute Opaque copies of the Document numbering +
If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a publicly-accessible computer-network location containing a complete @@ -637,49 +673,49 @@ until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public. -
It is requested, but not required, that you contact the authors of the +
It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document. -
You may copy and distribute a Modified Version of the Document under +
You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: -
If the Modified Version includes new front-matter sections or +
If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles. -
You may add a section entitled "Endorsements", provided it contains +
You may add a section entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard. -
You may add a passage of up to five words as a Front-Cover Text, and a +
You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or @@ -734,20 +770,20 @@ by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one. -
The author(s) and publisher(s) of the Document do not by this License +
The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version. -
You may combine the Document with other documents released under this +
You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice. -
The combined work need only contain one copy of this License, and +
The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by @@ -756,28 +792,28 @@ author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work. -
In the combination, you must combine any sections entitled "History" +
In the combination, you must combine any sections entitled "History" in the various original documents, forming one section entitled "History"; likewise combine any sections entitled "Acknowledgments", and any sections entitled "Dedications". You must delete all sections entitled "Endorsements." -
You may make a collection consisting of the Document and other documents +
You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects. -
You may extract a single document from such a collection, and distribute +
You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document. -
A compilation of the Document or its derivatives with other separate +
A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, does not as a whole count as a Modified Version of the Document, provided no compilation copyright is claimed for the @@ -786,15 +822,15 @@ License does not apply to the other self-contained works thus compiled with the Document, on account of their being thus compiled, if they are not themselves derivative works of the Document. -
If the Cover Text requirement of section 3 is applicable to these +
If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one quarter of the entire aggregate, the Document's Cover Texts may be placed on covers that surround only the Document within the aggregate. Otherwise they must appear on covers around the whole aggregate. -
Translation is considered a kind of modification, so you may +
Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include @@ -805,9 +841,9 @@ original English version of this License. In case of a disagreement between the translation and the original English version of this License, the original English version will prevail. -
You may not copy, modify, sublicense, or distribute the Document except +
You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, @@ -815,15 +851,15 @@ parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. -
The Free Software Foundation may publish new, revised versions +
The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/. -
Each version of the License is given a distinguishing version number. +
Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or @@ -831,57 +867,51 @@ of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. - + -
To use this License in a document you have written, include a copy of +
To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and
license notices just after the title page:
-
Copyright (C) year your name. - Permission is granted to copy, distribute and/or modify this document - under the terms of the GNU Free Documentation License, Version 1.1 - or any later version published by the Free Software Foundation; - with the Invariant Sections being list their titles, with the - Front-Cover Texts being list, and with the Back-Cover Texts being list. - A copy of the license is included in the section entitled ``GNU - Free Documentation License''. -+
Copyright (C) year your name. + Permission is granted to copy, distribute and/or modify this document + under the terms of the GNU Free Documentation License, Version 1.1 + or any later version published by the Free Software Foundation; + with the Invariant Sections being list their titles, with the + Front-Cover Texts being list, and with the Back-Cover Texts being list. + A copy of the license is included in the section entitled ``GNU + Free Documentation License''. +-
If you have no Invariant Sections, write "with no Invariant Sections" +
If you have no Invariant Sections, write "with no Invariant Sections" instead of saying which ones are invariant. If you have no Front-Cover Texts, write "no Front-Cover Texts" instead of "Front-Cover Texts being list"; likewise for Back-Cover Texts. -
If your document contains nontrivial examples of program code, we +
If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. +