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252 lines
8.2 KiB
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252 lines
8.2 KiB
Plaintext
<!doctype linuxdoc system>
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<article>
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<title>cc65 Library Overview
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<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
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<date>2000-12-02, 2002-11-26
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<abstract>
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An overview over the runtime and C libraries that come with the cc65 compiler,
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including a discussion of the differences to the ISO standard.
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</abstract>
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<!-- Table of contents -->
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<toc>
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<!-- Begin the document -->
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<sect>Overview<p>
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This file contains a short overview of the libraries available for the cc65 C
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compiler. Please have a look at the <htmlurl url="funcref.html" name="function
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reference"> for a list function by function. Since the function reference is
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not complete (I'm working on that) it may happen that you don't find a
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specific function. In this case, have a look into the header files. All
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functions, that are not defined by the ISO C standard have a short comment in
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the headers, explaining their use.
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<sect>ISO C compatible library<p>
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The C library contains a large subset of the ISO C library. Functions are
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usually missing in areas, where there is no support on typical 6502 systems.
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Wide character sets are an example for this.
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I will not go into detail about the ISO functions. If a function is not
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mentioned here explicitly, expect it to be available and to behave as defined
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in the C standard.
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Functions that are <em/not/ available:
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<itemize>
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<item><tt>tmpfile/tmpnam</tt>
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<p>
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<item><tt>system</tt>
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<p>
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<item>All functions that handle floating point numbers in some manner.
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<p>
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<item>The <tt/ldiv/ function (cc65 is currently not able to return structs
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with a size not equal to 1, 2 or 4 bytes by value).
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<p>
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<item>All functions handling wide character strings.
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<p>
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<item>Signals and all related functions (having <tt/SIGSEGV/ would be
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cool:-)
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<p>
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<item><tt>setbuf/setvbuf</tt>
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</itemize>
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Functions not available on all supported systems:
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<itemize>
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<item><tt>fopen/fread/fwrite/fclose/fputs/fgets/fscanf</tt>: The functions
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are built on open/read/write/close. These latter functions are not available
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on all systems.
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<p>
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<item><tt>ftell/fseek/fgetpos/fsetpos</tt>: Support depends on the
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capabilities of the target machine.
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<p>
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<item><tt>rename/remove/rewind</tt>: Support depends on the capabilities of
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the target machine.
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<p>
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<item><tt>time</tt>: Since many of the supported systems do not have a real
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time clock, which means that the <tt/time/ function is not available. Please
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note that the other functions from <tt/time.h/ <em/are/ available.
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</itemize>
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Functions that are limited in any way:
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<itemize>
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<item><tt>strcspn/strpbrk/strspn</tt>: These functions have a length
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limitation of 256 for the second string argument. Since this string gives a
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character set, and there are only 256 distinct characters, this shouldn't be
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a problem.
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<p>
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<item><tt>getenv</tt>: Since there is no such thing as an environment on all
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supported systems, the <tt/getenv/ function will always return a <tt/NULL/
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pointer.
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<p>
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<item><tt>locale</tt>: There is no other locale than the "C" locale. The
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native locale is identical to the "C" locale.
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</itemize>
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In addition to these limitations, some more functions are limited if inlined
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versions are requested by using -Os:
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<itemize>
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<item>The <tt/strlen/ function only works for strings with a maximum length
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of 255 characters.
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<p>
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<item>The <tt/isxxx/ character classification functions from
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<tt/<ctype.h>/ will give unpredictable results if the argument is not
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in character range (0..255). This limitation may be removed by #undef'ing
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the function name (when using <tt/-Os/, the functions are actually macros
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that expand to inline assembler code, but the real functions are still
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available if the macro definition is removed).
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</itemize>
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<sect>CPU specific stuff - 6502.h<p>
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The header file 6502.h contains some functions that make only sense with the
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6502 CPU. Examples are macros to insert more or less useful instructions into
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your C code, or a function to call arbitrary machine language subroutines,
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passing registers in and out.
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<sect>Target specific stuff<p>
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For each supported system there's a header file that contains calls or defines
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specific for this system. So, when programming for the C64, include c64.h, for
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the C128, include c128.h and so on. To make the task for the Commodore systems
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easier, there is also a header file named cbm.h that will define stuff common
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for all CBM systems, and include the header file for the specific target
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system.
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The header files contain
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<itemize>
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<item>Defines for special keys (like function keys)
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<item>Defines for special characters (like the graphics characters)
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<item>Variables with a fixed address in memory that may be used to access
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special hardware. For the C64 and C128 there is a variable struct named
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<tt/SID/. Writing to the fields of this struct will write to the SID device
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instead. Using these variables will make your program more readable and more
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portable. Don't fear ineffective code when using these variables, the
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compiler will translate reads and writes to these structs into direct memory
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accesses.
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<item>Other routines that make only sense for a specific system. One example
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are routines to write memory locations in the system bank for the CBM PET-II
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family.
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</itemize>
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<sect>Direct console I/O - <tt/conio.h/<p>
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The <tt/conio.h/ header file contains a large set of functions that do screen
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and keyboard I/O. The functions will write directly to the screen or poll the
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keyboard directly with no more help from the operating system than needed.
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This has some disadvantages, but on the other side it's fast and reasonably
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portable. conio implementations exist for the following targets:
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<itemize>
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<item>apple2
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<item>apple2enh
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<item>atari
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<item>atmos
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<item>c16 (works also for the c116 with up to 32K memory)
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<item>c64
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<item>c128
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<item>plus4 (or expanded c16/c116)
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<item>cbm510 (40 column video)
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<item>cbm610 (all CBM series-II computers with 80 column video)
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<item>geos-apple
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<item>geos-cbm
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<item>nes
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<item>pet (all CBM PET systems except the 2001)
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<item>vic20
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</itemize>
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The conio.h header file does also include the system specific header files
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which define constants for special characters and keys.
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<sect>Using the joystick - <tt/joystick.h/<p>
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For systems that have a joystick, <tt/joystick.h/ will define a subroutine to
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read the current value, including constants to evaluate the result of this
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function. To help in writing portable code, the header file will define the
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symbol <tt/__JOYSTICK__/ on systems that have a joystick.
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<sect>Using a mouse - <tt/mouse.h/<p>
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Some target machines support a mouse. Mouse support is currently available for
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the following targets:
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<itemize>
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<item>apple2
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<item>apple2enh
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<item>atari
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<item>c64
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<item>c128
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<item>cbm510
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</itemize>
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The available functions are declared in <tt/mouse.h/ To help writing portable
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code, the header file will define the symbol <tt/__MOUSE__/ in systems that
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support a mouse.
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<sect>Bugs/Feedback<p>
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If you have problems using the library, if you find any bugs, or if you're
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doing something interesting with it, I would be glad to hear from you. Feel
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free to contact me by email (<htmlurl url="mailto:uz@cc65.org"
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name="uz@cc65.org">).
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<sect>Copyright<p>
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This C runtime library implementation for the cc65 compiler is (C)
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Copyright 1998-2002 Ullrich von Bassewitz. For usage of the binaries
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and/or sources the following conditions do apply:
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This software is provided 'as-is', without any expressed or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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<enum>
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<item> The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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<item> Altered source versions must be plainly marked as such, and must not
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be misrepresented as being the original software.
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<item> This notice may not be removed or altered from any source
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distribution.
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</enum>
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</article>
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