LuaJIT is fully upwards-compatible with Lua 5.1. It supports all
» standard Lua
@@ -149,13 +150,33 @@ xpcall(f, err [,args...]) passes arguments
which is called in a protected context.
loadfile() etc. handle UTF-8 source code
+load*() handle UTF-8 source code
Non-ASCII characters are handled transparently by the Lua source code parser. This allows the use of UTF-8 characters in identifiers and strings. A UTF-8 BOM is skipped at the start of the source code.
+load*() add a mode parameter
++As an extension from Lua 5.2, the functions loadstring(), +loadfile() and (new) load() add an optional +mode parameter. +
++The default mode string is "bt", which allows loading of both +source code and bytecode. Use "t" to allow only source code +or "b" to allow only bytecode to be loaded. +
++By default, the load* functions generate the native bytecode format. +For cross-compilation purposes, add W to the mode string to +force the 32 bit format and X to force the 64 bit format. +Add both to force the opposite format. Note that non-native bytecode +generated by load* cannot be run, but can still be passed +to string.dump. +
+tostring() etc. canonicalize NaN and ±Inf
All number-to-string conversions consistently convert non-finite numbers @@ -175,26 +196,33 @@
tonumber() etc. use builtin string to number conversi
numbers (e.g. 0x1.5p-3).
-string.dump(f [,strip]) generates portable bytecode
+string.dump(f [,mode]) generates portable bytecode
An extra argument has been added to string.dump(). If set to -true, 'stripped' bytecode without debug information is -generated. This speeds up later bytecode loading and reduces memory -usage. See also the +true or to a string which contains the character s, +'stripped' bytecode without debug information is generated. This speeds +up later bytecode loading and reduces memory usage. See also the -b command line option.
The generated bytecode is portable and can be loaded on any architecture -that LuaJIT supports, independent of word size or endianess. However, the -bytecode compatibility versions must match. Bytecode stays compatible -for dot releases (x.y.0 → x.y.1), but may change with major or -minor releases (2.0 → 2.1) or between any beta release. Foreign -bytecode (e.g. from Lua 5.1) is incompatible and cannot be loaded. +that LuaJIT supports. However, the bytecode compatibility versions must +match. Bytecode only stays compatible within a major+minor version +(x.y.aaa → x.y.bbb), except for development branches. Foreign bytecode +(e.g. from Lua 5.1) is incompatible and cannot be loaded.
Note: LJ_GC64 mode requires a different frame layout, which implies -a different, incompatible bytecode format for all 64 bit ports. This may be -rectified in the future. +a different, incompatible bytecode format between 32 bit and 64 bit ports. +This may be rectified in the future. In the meantime, use the W +and X modes of the load* functions +for cross-compilation purposes. +
++Due to VM hardening, bytecode is not deterministic. Add d to the +mode string to dump it in a deterministic manner: identical source code +always gives a byte-for-byte identical bytecode dump. This feature is +mainly useful for reproducible builds.
table.new(narray, nhash) allocates a pre-sized table
@@ -227,7 +255,7 @@Enhanced PRNG for math.random()
LuaJIT uses a Tausworthe PRNG with period 2^223 to implement math.random() and math.randomseed(). The quality of the PRNG results is much superior compared to the standard Lua -implementation, which uses the platform-specific ANSI rand(). +implementation, which uses the platform-specific ANSI rand().The PRNG generates the same sequences from the same seeds on all @@ -238,6 +266,10 @@
Enhanced PRNG for math.random()
preserve uniformity.+Call math.randomseed() without any arguments to seed it from +system entropy. +
+Important: Neither this nor any other PRNG based on the simplistic math.random() API is suitable for cryptographic use.
@@ -275,7 +307,7 @@Extensions from Lua 5.2
- goto and ::labels::. -
- Hex escapes '\x3F' and '\*' escape in strings. +
- Hex escapes '\x3F' and '\z' escape in strings.
- load(string|reader [, chunkname [,mode [,env]]]).
- loadstring() is an alias for load().
- loadfile(filename [,mode [,env]]). @@ -415,9 +447,7 @@
- Lua errors can be caught on the C++ side with catch(...).
-The corresponding Lua error message can be retrieved from the Lua stack.
-For MSVC for Windows 64 bit this requires compilation of your C++ code -with /EHa.
+The corresponding Lua error message can be retrieved from the Lua stack.
- Throwing Lua errors across C++ frames is safe. C++ destructors will be called.