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介绍

Lua 应用比较广泛，主要是作为插件解释器。例如mysql proxy，VLC 等。Lua 源代码比较规范，代码也不长，2w 多行，分布也是比较均匀的，就想看一看，顺便在这里做个笔记。

lua 5.2.3 源码树

[will@iF8sg:~DOWN]% tree lua-5.2.3
lua-5.2.3
├── Makefile
├── README
├── doc
│   ├── contents.html
│   ├── logo.gif
│   ├── lua.1
│   ├── lua.css
│   ├── luac.1
│   ├── manual.css
│   ├── manual.html
│   ├── osi-certified-72x60.png
│   └── readme.html
└── src
    ├── Makefile
    ├── lapi.c
    ├── lapi.h
    ├── lauxlib.c
    ├── lauxlib.h
    ├── lbaselib.c
    ├── lbitlib.c
    ├── lcode.c
    ├── lcode.h
    ├── lcorolib.c
    ├── lctype.c
    ├── lctype.h
    ├── ldblib.c
    ├── ldebug.c
    ├── ldebug.h
    ├── ldo.c
    ├── ldo.h
    ├── ldump.c
    ├── lfunc.c
    ├── lfunc.h
    ├── lgc.c
    ├── lgc.h
    ├── linit.c
    ├── liolib.c
    ├── llex.c
    ├── llex.h
    ├── llimits.h
    ├── lmathlib.c
    ├── lmem.c
    ├── lmem.h
    ├── loadlib.c
    ├── lobject.c
    ├── lobject.h
    ├── lopcodes.c
    ├── lopcodes.h
    ├── loslib.c
    ├── lparser.c
    ├── lparser.h
    ├── lstate.c
    ├── lstate.h
    ├── lstring.c
    ├── lstring.h
    ├── lstrlib.c
    ├── ltable.c
    ├── ltable.h
    ├── ltablib.c
    ├── ltm.c
    ├── ltm.h
    ├── lua.c
    ├── lua.h
    ├── lua.hpp
    ├── luac.c
    ├── luaconf.h
    ├── lualib.h
    ├── lundump.c
    ├── lundump.h
    ├── lvm.c
    ├── lvm.h
    ├── lzio.c
    └── lzio.h
2 directories, 71 files

lua 5.2.3 代码量

[oxnz@iF8sg:tmp]% wc -l /Users/oxnz/Downloads/lua-5.2.3/src/*
     187 /Users/oxnz/Downloads/lua-5.2.3/src/Makefile
    1284 /Users/oxnz/Downloads/lua-5.2.3/src/lapi.c
      24 /Users/oxnz/Downloads/lua-5.2.3/src/lapi.h
     959 /Users/oxnz/Downloads/lua-5.2.3/src/lauxlib.c
     212 /Users/oxnz/Downloads/lua-5.2.3/src/lauxlib.h
     458 /Users/oxnz/Downloads/lua-5.2.3/src/lbaselib.c
     212 /Users/oxnz/Downloads/lua-5.2.3/src/lbitlib.c
     881 /Users/oxnz/Downloads/lua-5.2.3/src/lcode.c
      83 /Users/oxnz/Downloads/lua-5.2.3/src/lcode.h
     155 /Users/oxnz/Downloads/lua-5.2.3/src/lcorolib.c
      52 /Users/oxnz/Downloads/lua-5.2.3/src/lctype.c
      95 /Users/oxnz/Downloads/lua-5.2.3/src/lctype.h
     398 /Users/oxnz/Downloads/lua-5.2.3/src/ldblib.c
     593 /Users/oxnz/Downloads/lua-5.2.3/src/ldebug.c
      34 /Users/oxnz/Downloads/lua-5.2.3/src/ldebug.h
     681 /Users/oxnz/Downloads/lua-5.2.3/src/ldo.c
      46 /Users/oxnz/Downloads/lua-5.2.3/src/ldo.h
     173 /Users/oxnz/Downloads/lua-5.2.3/src/ldump.c
     161 /Users/oxnz/Downloads/lua-5.2.3/src/lfunc.c
      33 /Users/oxnz/Downloads/lua-5.2.3/src/lfunc.h
    1220 /Users/oxnz/Downloads/lua-5.2.3/src/lgc.c
     157 /Users/oxnz/Downloads/lua-5.2.3/src/lgc.h
      67 /Users/oxnz/Downloads/lua-5.2.3/src/linit.c
     666 /Users/oxnz/Downloads/lua-5.2.3/src/liolib.c
     530 /Users/oxnz/Downloads/lua-5.2.3/src/llex.c
      78 /Users/oxnz/Downloads/lua-5.2.3/src/llex.h
     309 /Users/oxnz/Downloads/lua-5.2.3/src/llimits.h
     279 /Users/oxnz/Downloads/lua-5.2.3/src/lmathlib.c
      99 /Users/oxnz/Downloads/lua-5.2.3/src/lmem.c
      57 /Users/oxnz/Downloads/lua-5.2.3/src/lmem.h
     725 /Users/oxnz/Downloads/lua-5.2.3/src/loadlib.c
     287 /Users/oxnz/Downloads/lua-5.2.3/src/lobject.c
     607 /Users/oxnz/Downloads/lua-5.2.3/src/lobject.h
     107 /Users/oxnz/Downloads/lua-5.2.3/src/lopcodes.c
     288 /Users/oxnz/Downloads/lua-5.2.3/src/lopcodes.h
     323 /Users/oxnz/Downloads/lua-5.2.3/src/loslib.c
    1638 /Users/oxnz/Downloads/lua-5.2.3/src/lparser.c
     119 /Users/oxnz/Downloads/lua-5.2.3/src/lparser.h
     323 /Users/oxnz/Downloads/lua-5.2.3/src/lstate.c
     228 /Users/oxnz/Downloads/lua-5.2.3/src/lstate.h
     185 /Users/oxnz/Downloads/lua-5.2.3/src/lstring.c
      46 /Users/oxnz/Downloads/lua-5.2.3/src/lstring.h
    1019 /Users/oxnz/Downloads/lua-5.2.3/src/lstrlib.c
     588 /Users/oxnz/Downloads/lua-5.2.3/src/ltable.c
      45 /Users/oxnz/Downloads/lua-5.2.3/src/ltable.h
     283 /Users/oxnz/Downloads/lua-5.2.3/src/ltablib.c
      77 /Users/oxnz/Downloads/lua-5.2.3/src/ltm.c
      57 /Users/oxnz/Downloads/lua-5.2.3/src/ltm.h
     497 /Users/oxnz/Downloads/lua-5.2.3/src/lua.c
     444 /Users/oxnz/Downloads/lua-5.2.3/src/lua.h
       9 /Users/oxnz/Downloads/lua-5.2.3/src/lua.hpp
     432 /Users/oxnz/Downloads/lua-5.2.3/src/luac.c
     551 /Users/oxnz/Downloads/lua-5.2.3/src/luaconf.h
      55 /Users/oxnz/Downloads/lua-5.2.3/src/lualib.h
     258 /Users/oxnz/Downloads/lua-5.2.3/src/lundump.c
      28 /Users/oxnz/Downloads/lua-5.2.3/src/lundump.h
     867 /Users/oxnz/Downloads/lua-5.2.3/src/lvm.c
      44 /Users/oxnz/Downloads/lua-5.2.3/src/lvm.h
      76 /Users/oxnz/Downloads/lua-5.2.3/src/lzio.c
      65 /Users/oxnz/Downloads/lua-5.2.3/src/lzio.h
   20454 total

README

[oxnz@iF8sg:lua-5.2.3]% cat README
This is Lua 5.2.3, released on 11 Nov 2013.
For installation instructions, license details, and

further information about Lua, see doc/readme.html.

Makefile

lua 的 Makefile 可以看得出是手写的，不是 autotools 自动生成的，所以还是仔细看一下编译过程，以便对 lua 有一个总体的了解。

[oxnz@iF8sg:lua-5.2.3]% cat Makefile
# Makefile for installing Lua
# See doc/readme.html for installation and customization instructions.
 == CHANGE THE SETTINGS BELOW TO SUIT YOUR ENVIRONMENT =======================
 Your platform. See PLATS for possible values.
PLAT= none
 Where to install. The installation starts in the src and doc directories,
 so take care if INSTALL_TOP is not an absolute path. See the local target.
 You may want to make INSTALL_LMOD and INSTALL_CMOD consistent with
 LUA_ROOT, LUA_LDIR, and LUA_CDIR in luaconf.h.
INSTALL_TOP= /usr/local

INSTALL_BIN= $(INSTALL_TOP)/bin

INSTALL_INC= $(INSTALL_TOP)/include

INSTALL_LIB= $(INSTALL_TOP)/lib

INSTALL_MAN= $(INSTALL_TOP)/man/man1

INSTALL_LMOD= $(INSTALL_TOP)/share/lua/$V

INSTALL_CMOD= $(INSTALL_TOP)/lib/lua/$V
 How to install. If your install program does not support "-p", then
 you may have to run ranlib on the installed liblua.a.
INSTALL= install -p

INSTALL_EXEC= $(INSTALL) -m 0755

INSTALL_DATA= $(INSTALL) -m 0644
 
 If you don't have "install" you can use "cp" instead.
 INSTALL= cp -p
 INSTALL_EXEC= $(INSTALL)
 INSTALL_DATA= $(INSTALL)
 Other utilities.
MKDIR= mkdir -p

RM= rm -f
 == END OF USER SETTINGS – NO NEED TO CHANGE ANYTHING BELOW THIS LINE =======
 Convenience platforms targets.
PLATS= aix ansi bsd freebsd generic linux macosx mingw posix solaris
 What to install.
TO_BIN= lua luac

TO_INC= lua.h luaconf.h lualib.h lauxlib.h lua.hpp

TO_LIB= liblua.a

TO_MAN= lua.1 luac.1
 Lua version and release.
V= 5.2

R= $V.3
 Targets start here.
all:	$(PLAT)
$(PLATS) clean:

cd src && $(MAKE) $@
test:	dummy

src/lua -v
install: dummy

cd src && $(MKDIR) $(INSTALL_BIN) $(INSTALL_INC) $(INSTALL_LIB) $(INSTALL_MAN) $(INSTALL_LMOD) $(INSTALL_CMOD)

cd src && $(INSTALL_EXEC) $(TO_BIN) $(INSTALL_BIN)

cd src && $(INSTALL_DATA) $(TO_INC) $(INSTALL_INC)

cd src && $(INSTALL_DATA) $(TO_LIB) $(INSTALL_LIB)

cd doc && $(INSTALL_DATA) $(TO_MAN) $(INSTALL_MAN)
uninstall:

cd src && cd $(INSTALL_BIN) && $(RM) $(TO_BIN)

cd src && cd $(INSTALL_INC) && $(RM) $(TO_INC)

cd src && cd $(INSTALL_LIB) && $(RM) $(TO_LIB)

cd doc && cd $(INSTALL_MAN) && $(RM) $(TO_MAN)
local:

$(MAKE) install INSTALL_TOP=…/install
none:

@echo "Please do 'make PLATFORM' where PLATFORM is one of these:"

@echo "   $(PLATS)"

@echo "See doc/readme.html for complete instructions."
 make may get confused with test/ and install/
dummy:
 echo config parameters
echo:

@cd src && $(MAKE) -s echo

@echo "PLAT= $(PLAT)"

@echo "V= $V"

@echo "R= $R"

@echo "TO_BIN= $(TO_BIN)"

@echo "TO_INC= $(TO_INC)"

@echo "TO_LIB= $(TO_LIB)"

@echo "TO_MAN= $(TO_MAN)"

@echo "INSTALL_TOP= $(INSTALL_TOP)"

@echo "INSTALL_BIN= $(INSTALL_BIN)"

@echo "INSTALL_INC= $(INSTALL_INC)"

@echo "INSTALL_LIB= $(INSTALL_LIB)"

@echo "INSTALL_MAN= $(INSTALL_MAN)"

@echo "INSTALL_LMOD= $(INSTALL_LMOD)"

@echo "INSTALL_CMOD= $(INSTALL_CMOD)"

@echo "INSTALL_EXEC= $(INSTALL_EXEC)"

@echo "INSTALL_DATA= $(INSTALL_DATA)"
 echo pkg-config data
pc:

@echo "version=R"
	@echo "prefix=(INSTALL_TOP)"

@echo "libdir=(INSTALL_LIB)"
	@echo "includedir=(INSTALL_INC)"
 list targets that do not create files (but not all makes understand .PHONY)
.PHONY: all $(PLATS) clean test install local none dummy echo pecho lecho
 (end of Makefile)

END OF USER SETTINGS之前是一些配置项目。诸如指定平台，各部分安装目录和安装程序以及依赖的辅助程序等。之后列出了支持的平台，需要安装的各文件，版本号。最后到了熟悉的all:，其后面是 $(PLAT)，就是平台，但到此时为止还是 none。所以执行 make 会出现如下信息：

[oxnz@iF8sg:lua-5.2.3]% make
Please do 'make PLATFORM' where PLATFORM is one of these:
   aix ansi bsd freebsd generic linux macosx mingw posix solaris
See doc/readme.html for complete instructions.

告诉你选择一个列出的平台。整个 Makefile 比较直白，没有什么太高深的东西。由于我目前在使用 OS X 系统，所以这个根目录的 Makefile 最终的编译指令就是 cd src && make macosx，所以我们去看看 src 目录下的 Makefile。

src/Makefile

由于这个 Makefile 略长，所以分割开来看好了。首先是用户设置：

# Makefile for building Lua
# See ../doc/readme.html for installation and customization instructions.
 == CHANGE THE SETTINGS BELOW TO SUIT YOUR ENVIRONMENT =======================
 Your platform. See PLATS for possible values.
PLAT= none
CC= gcc

CFLAGS= -O2 -Wall -DLUA_COMPAT_ALL $(SYSCFLAGS) $(MYCFLAGS)

LDFLAGS= $(SYSLDFLAGS) $(MYLDFLAGS)

LIBS= -lm $(SYSLIBS) $(MYLIBS)
AR= ar rcu

RANLIB= ranlib

RM= rm -f
SYSCFLAGS=

SYSLDFLAGS=

SYSLIBS=
MYCFLAGS=

MYLDFLAGS=

MYLIBS=

MYOBJS=
 == END OF USER SETTINGS – NO NEED TO CHANGE ANYTHING BELOW THIS LINE =======

其中指定了编译工具链及其参数。接着是一些变量定义：

PLATS= aix ansi bsd freebsd generic linux macosx mingw posix solaris
LUA_A=	liblua.a

CORE_O=	lapi.o lcode.o lctype.o ldebug.o ldo.o ldump.o lfunc.o lgc.o llex.o

lmem.o lobject.o lopcodes.o lparser.o lstate.o lstring.o ltable.o

ltm.o lundump.o lvm.o lzio.o

LIB_O=	lauxlib.o lbaselib.o lbitlib.o lcorolib.o ldblib.o liolib.o

lmathlib.o loslib.o lstrlib.o ltablib.o loadlib.o linit.o

BASE_O= $(CORE_O) $(LIB_O) $(MYOBJS)
LUA_T=	lua

LUA_O=	lua.o
LUAC_T=	luac

LUAC_O=	luac.o
ALL_O= $(BASE_O) $(LUA_O) $(LUAC_O)

ALL_T= $(LUA_A) $(LUA_T) $(LUAC_T)

ALL_A= $(LUA_A)

说明了整个的.o 文件和.a 文件，下面是目标以及规则定义：

# Targets start here.
default: $(PLAT)
all:	$(ALL_T)
o:	$(ALL_O)
a:	$(ALL_A)
$(LUA_A): $(BASE_O)

$(AR) $@ $(BASE_O)

$(RANLIB) $@
$(LUA_T): $(LUA_O) $(LUA_A)

$(CC) -o $@ $(LDFLAGS) $(LUA_O) $(LUA_A) $(LIBS)
$(LUAC_T): $(LUAC_O) $(LUA_A)

$(CC) -o $@ $(LDFLAGS) $(LUAC_O) $(LUA_A) $(LIBS)
clean:

$(RM) $(ALL_T) $(ALL_O)
depend:

@$(CC) $(CFLAGS) -MM l*.c
echo:

@echo "PLAT= $(PLAT)"

@echo "CC= $(CC)"

@echo "CFLAGS= $(CFLAGS)"

@echo "LDFLAGS= $(SYSLDFLAGS)"

@echo "LIBS= $(LIBS)"

@echo "AR= $(AR)"

@echo "RANLIB= $(RANLIB)"

@echo "RM= $(RM)"
 Convenience targets for popular platforms
ALL= all
none:

@echo "Please do 'make PLATFORM' where PLATFORM is one of these:"

@echo "   $(PLATS)"
aix:

$(MAKE) $(ALL) CC="xlc" CFLAGS="-O2 -DLUA_USE_POSIX -DLUA_USE_DLOPEN" SYSLIBS="-ldl" SYSLDFLAGS="-brtl -bexpall"
ansi:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_ANSI"
bsd:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_POSIX -DLUA_USE_DLOPEN" SYSLIBS="-Wl,-E"
freebsd:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_LINUX" SYSLIBS="-Wl,-E -lreadline"
generic: $(ALL)
linux:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_LINUX" SYSLIBS="-Wl,-E -ldl -lreadline"
macosx:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_MACOSX" SYSLIBS="-lreadline" CC=cc
mingw:

(MAKE) "LUA_A=lua52.dll" "LUA_T=lua.exe"
	"AR=(CC) -shared -o" "RANLIB=strip --strip-unneeded"

"SYSCFLAGS=-DLUA_BUILD_AS_DLL" "SYSLIBS=" "SYSLDFLAGS=-s" lua.exe

$(MAKE) "LUAC_T=luac.exe" luac.exe
posix:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_POSIX"
solaris:

$(MAKE) $(ALL) SYSCFLAGS="-DLUA_USE_POSIX -DLUA_USE_DLOPEN" SYSLIBS="-ldl"
 list targets that do not create files (but not all makes understand .PHONY)
.PHONY: all $(PLATS) default o a clean depend echo none
 DO NOT DELETE

最后是具体的.o 文件的依赖关系：

lapi.o: lapi.c lua.h luaconf.h lapi.h llimits.h lstate.h lobject.h ltm.h
 lzio.h lmem.h ldebug.h ldo.h lfunc.h lgc.h lstring.h ltable.h lundump.h
 lvm.h
lauxlib.o: lauxlib.c lua.h luaconf.h lauxlib.h
lbaselib.o: lbaselib.c lua.h luaconf.h lauxlib.h lualib.h
lbitlib.o: lbitlib.c lua.h luaconf.h lauxlib.h lualib.h
lcode.o: lcode.c lua.h luaconf.h lcode.h llex.h lobject.h llimits.h
 lzio.h lmem.h lopcodes.h lparser.h ldebug.h lstate.h ltm.h ldo.h lgc.h
 lstring.h ltable.h lvm.h
lcorolib.o: lcorolib.c lua.h luaconf.h lauxlib.h lualib.h
lctype.o: lctype.c lctype.h lua.h luaconf.h llimits.h
ldblib.o: ldblib.c lua.h luaconf.h lauxlib.h lualib.h
ldebug.o: ldebug.c lua.h luaconf.h lapi.h llimits.h lstate.h lobject.h
 ltm.h lzio.h lmem.h lcode.h llex.h lopcodes.h lparser.h ldebug.h ldo.h
 lfunc.h lstring.h lgc.h ltable.h lvm.h
ldo.o: ldo.c lua.h luaconf.h lapi.h llimits.h lstate.h lobject.h ltm.h
 lzio.h lmem.h ldebug.h ldo.h lfunc.h lgc.h lopcodes.h lparser.h
 lstring.h ltable.h lundump.h lvm.h
ldump.o: ldump.c lua.h luaconf.h lobject.h llimits.h lstate.h ltm.h
 lzio.h lmem.h lundump.h
lfunc.o: lfunc.c lua.h luaconf.h lfunc.h lobject.h llimits.h lgc.h
 lstate.h ltm.h lzio.h lmem.h
lgc.o: lgc.c lua.h luaconf.h ldebug.h lstate.h lobject.h llimits.h ltm.h
 lzio.h lmem.h ldo.h lfunc.h lgc.h lstring.h ltable.h
linit.o: linit.c lua.h luaconf.h lualib.h lauxlib.h
liolib.o: liolib.c lua.h luaconf.h lauxlib.h lualib.h
llex.o: llex.c lua.h luaconf.h lctype.h llimits.h ldo.h lobject.h
 lstate.h ltm.h lzio.h lmem.h llex.h lparser.h lstring.h lgc.h ltable.h
lmathlib.o: lmathlib.c lua.h luaconf.h lauxlib.h lualib.h
lmem.o: lmem.c lua.h luaconf.h ldebug.h lstate.h lobject.h llimits.h
 ltm.h lzio.h lmem.h ldo.h lgc.h
loadlib.o: loadlib.c lua.h luaconf.h lauxlib.h lualib.h
lobject.o: lobject.c lua.h luaconf.h lctype.h llimits.h ldebug.h lstate.h
 lobject.h ltm.h lzio.h lmem.h ldo.h lstring.h lgc.h lvm.h
lopcodes.o: lopcodes.c lopcodes.h llimits.h lua.h luaconf.h
loslib.o: loslib.c lua.h luaconf.h lauxlib.h lualib.h
lparser.o: lparser.c lua.h luaconf.h lcode.h llex.h lobject.h llimits.h
 lzio.h lmem.h lopcodes.h lparser.h ldebug.h lstate.h ltm.h ldo.h lfunc.h
 lstring.h lgc.h ltable.h
lstate.o: lstate.c lua.h luaconf.h lapi.h llimits.h lstate.h lobject.h
 ltm.h lzio.h lmem.h ldebug.h ldo.h lfunc.h lgc.h llex.h lstring.h
 ltable.h
lstring.o: lstring.c lua.h luaconf.h lmem.h llimits.h lobject.h lstate.h
 ltm.h lzio.h lstring.h lgc.h
lstrlib.o: lstrlib.c lua.h luaconf.h lauxlib.h lualib.h
ltable.o: ltable.c lua.h luaconf.h ldebug.h lstate.h lobject.h llimits.h
 ltm.h lzio.h lmem.h ldo.h lgc.h lstring.h ltable.h lvm.h
ltablib.o: ltablib.c lua.h luaconf.h lauxlib.h lualib.h
ltm.o: ltm.c lua.h luaconf.h lobject.h llimits.h lstate.h ltm.h lzio.h
 lmem.h lstring.h lgc.h ltable.h
lua.o: lua.c lua.h luaconf.h lauxlib.h lualib.h
luac.o: luac.c lua.h luaconf.h lauxlib.h lobject.h llimits.h lstate.h
 ltm.h lzio.h lmem.h lundump.h ldebug.h lopcodes.h
lundump.o: lundump.c lua.h luaconf.h ldebug.h lstate.h lobject.h
 llimits.h ltm.h lzio.h lmem.h ldo.h lfunc.h lstring.h lgc.h lundump.h
lvm.o: lvm.c lua.h luaconf.h ldebug.h lstate.h lobject.h llimits.h ltm.h
 lzio.h lmem.h ldo.h lfunc.h lgc.h lopcodes.h lstring.h ltable.h lvm.h
lzio.o: lzio.c lua.h luaconf.h llimits.h lmem.h lstate.h lobject.h ltm.h
 lzio.h

luaconf.h

这个头文件中定义了一些设置信息，放在这里以便后续参考。

[oxnz@iF8sg:src]% grep @@ luaconf.h
** Search for "@@" to find all configurable definitions.
@@ LUA_ANSI controls the use of non-ansi features.
@@ LUA_USE_POSIX includes all functionality listed as X/Open System
@@ LUA_PATH_DEFAULT is the default path that Lua uses to look for
@@ LUA_CPATH_DEFAULT is the default path that Lua uses to look for
@@ LUA_DIRSEP is the directory separator (for submodules).
@@ LUA_ENV is the name of the variable that holds the current
@@ environment, used to access global names.
@@ LUA_API is a mark for all core API functions.
@@ LUALIB_API is a mark for all auxiliary library functions.
@@ LUAMOD_API is a mark for all standard library opening functions.
@@ LUAI_FUNC is a mark for all extern functions that are not to be
@@ LUAI_DDEF and LUAI_DDEC are marks for all extern (const) variables
@@ LUA_QL describes how error messages quote program elements.
@@ LUA_IDSIZE gives the maximum size for the description of the source
@@ luai_writestring/luai_writeline define how 'print' prints its results.
@@ luai_writestringerror defines how to print error messages.
@@ LUAI_MAXSHORTLEN is the maximum length for short strings, that is,
@@ LUA_COMPAT_ALL controls all compatibility options.
@@ LUA_COMPAT_UNPACK controls the presence of global 'unpack'.
@@ LUA_COMPAT_LOADERS controls the presence of table 'package.loaders'.
@@ macro 'lua_cpcall' emulates deprecated function lua_cpcall.
@@ LUA_COMPAT_LOG10 defines the function 'log10' in the math library.
@@ LUA_COMPAT_LOADSTRING defines the function 'loadstring' in the base
@@ LUA_COMPAT_MAXN defines the function 'maxn' in the table library.
@@ The following macros supply trivial compatibility for some
@@ LUA_COMPAT_MODULE controls compatibility with previous
@@ LUAI_BITSINT defines the number of bits in an int.
@@ LUA_INT32 is an signed integer with exactly 32 bits.
@@ LUAI_UMEM is an unsigned integer big enough to count the total
@@ LUAI_MEM is a signed integer big enough to count the total memory
@@ LUAI_MAXSTACK limits the size of the Lua stack.
@@ LUAL_BUFFERSIZE is the buffer size used by the lauxlib buffer system.
@@ LUA_NUMBER is the type of numbers in Lua.
@@ LUAI_UACNUMBER is the result of an 'usual argument conversion'
@@ LUA_NUMBER_SCAN is the format for reading numbers.
@@ LUA_NUMBER_FMT is the format for writing numbers.
@@ lua_number2str converts a number to a string.
@@ LUAI_MAXNUMBER2STR is maximum size of previous conversion.
@@ l_mathop allows the addition of an 'l' or 'f' to all math operations
@@ lua_str2number converts a decimal numeric string to a number.
@@ lua_strx2number converts an hexadecimal numeric string to a number.
@@ The luai_num* macros define the primitive operations over numbers.
@@ LUA_INTEGER is the integral type used by lua_pushinteger/lua_tointeger.
@@ LUA_UNSIGNED is the integral type used by lua_pushunsigned/lua_tounsigned.
@@ LUA_MSASMTRICK uses Microsoft assembler to avoid clashes with a
@@ LUA_IEEE754TRICK uses a trick that should work on any machine
@@ LUA_IEEELL extends the trick to LUA_INTEGER; should only be
@@ LUA_IEEEENDIAN is the endianness of doubles in your machine
@@ LUA_NANTRICK controls the use of a trick to pack all types into

main

接下来就要进入 lua.c 文件中的 main 函数了，具体如下：

int main (int argc, char **argv) {
  int status, result;
  lua_State *L = luaL_newstate();  /* create state */
  if (L == NULL) {
    l_message(argv[0], "cannot create state: not enough memory");
    return EXIT_FAILURE;
  }
  /* call 'pmain' in protected mode */
  lua_pushcfunction(L, &pmain);
  lua_pushinteger(L, argc);  /* 1st argument */
  lua_pushlightuserdata(L, argv); /* 2nd argument */
  status = lua_pcall(L, 2, 1, 0);
  result = lua_toboolean(L, -1);  /* get result */
  finalreport(L, status);
  lua_close(L);
  return (result && status == LUA_OK) ? EXIT_SUCCESS : EXIT_FAILURE;
}

lua_State 结构在lstate.h 中定义，如果创建失败，则错误退出。否则在保护模式(protected mode)中调用 pmain。接着传入 argc 与 argv，之后的status = lua_pcall(L, 2, 1, 0);中直接给出了2、1、0三个数字，对应到 lua.h 文件中得宏：

#define lua_pcall(L,n,r,f)  lua_pcallk(L, (n), (r), (f), 0, NULL)

可以看出，其实是调用了 lua_pcallk(L, (2), (1), (0), 0, NULL)。而看到下面的 lua_pcallk 定义就清楚了：

LUA_API int   (lua_pcallk) (lua_State *L, int nargs, int nresults, int errfunc,
                            int ctx, lua_CFunction k);

其中2赋给了 nargs，1赋给了 nresults，0赋给了 errfunc，ctx 被上一个宏设置为0，k 设置为 NULL。最后获取结果，报告状态，关闭之前创建的 L 并退出。其中 lua_pushcfunction(L, &pmain);被宏#define lua_pushcfunction(L,f) lua_pushcclosure(L, (f), 0)展开之后变成了 lua_pushcclosure(L, (pmain), 0),而lua_pushcclosure的定义为LUA_API void (lua_pushcclosure) (lua_State *L, lua_CFunction fn, int n);纵观整个 main，真正开始做事的应该是 lua_pcall 函数，也就是 lua_pcallk，看其定义：

LUA_API int lua_pcallk (lua_State *L, int nargs, int nresults, int errfunc,
                        int ctx, lua_CFunction k) {
  struct CallS c;
  int status;
  ptrdiff_t func;
  lua_lock(L);
  api_check(L, k == NULL || !isLua(L->ci),
    "cannot use continuations inside hooks");
  api_checknelems(L, nargs+1);
  api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
  checkresults(L, nargs, nresults);
  if (errfunc == 0)
    func = 0;
  else {
    StkId o = index2addr(L, errfunc);
    api_checkstackindex(L, errfunc, o);
    func = savestack(L, o);
  }
  c.func = L->top - (nargs+1);  /* function to be called */
  if (k == NULL || L->nny > 0) {  /* no continuation or no yieldable? */
    c.nresults = nresults;  /* do a 'conventional' protected call */
    status = luaD_pcall(L, f_call, &c, savestack(L, c.func), func);
  }
  else {  /* prepare continuation (call is already protected by 'resume') */
    CallInfo *ci = L->ci;
    ci->u.c.k = k;  /* save continuation */
    ci->u.c.ctx = ctx;  /* save context */
    /* save information for error recovery */
    ci->extra = savestack(L, c.func);
    ci->u.c.old_allowhook = L->allowhook;
    ci->u.c.old_errfunc = L->errfunc;
    L->errfunc = func;
    /* mark that function may do error recovery */
    ci->callstatus |= CIST_YPCALL;
    luaD_call(L, c.func, nresults, 1);  /* do the call */
    ci->callstatus &= ~CIST_YPCALL;
    L->errfunc = ci->u.c.old_errfunc;
    status = LUA_OK;  /* if it is here, there were no errors */
  }
  adjustresults(L, nresults);
  lua_unlock(L);
  return status;
}

限于篇幅，近期会作后续更新。