This is a low-level function. It completely bypasses the package and module system. Unlike require, it does not perform any path searching and does not automatically adds extensions. libname must be the complete file name of the C library, including if necessary a path and extension. funcname must be the exact name exported by the C library (which may depend on the C compiler and linker used).
This function is not supported by ANSI C. As such, it is only available on some platforms (Windows, Linux, Mac OS X, Solaris, BSD, plus other Unix systems that support the dlfcn standard).
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package.path
The path used by require to search for a Lua loader.
At start-up, Lua initializes this variable with the value of the environment variable LUA_PATH or with a default path defined in luaconf.h, if the environment variable is not defined. Any ";;" in the value of the environment variable is replaced by the default path.
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package.preload
A table to store loaders for specific modules (see require).
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package.seeall (module)
Sets a metatable for module with its __index field referring to the global environment, so that this module inherits values from the global environment. To be used as an option to function module.
5.4 - String Manipulation
This library provides generic functions for string manipulation, such as finding and extracting substrings, and pattern matching. When indexing a string in Lua, the first character is at position 1 (not at 0, as in C). Indices are allowed to be negative and are interpreted as indexing backwards, from the end of the string. Thus, the last character is at position -1, and so on.
The string library provides all its functions inside the table string. It also sets a metatable for strings where the __index field points to the string table. Therefore, you can use the string functions in object-oriented style. For instance, string.byte(s, i) can be written as s:byte(i).
The string library assumes one-byte character encodings.
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string.byte (s [, i [, j]])
Returns the internal numerical codes of the characters s[i], s[i+1], ···, s[j]. The default value for i is 1; the default value for j is i.
Note that numerical codes are not necessarily portable across platforms.
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string.char (···)
Receives zero or more integers. Returns a string with length equal to the number of arguments, in which each character has the internal numerical code equal to its corresponding argument.
Note that numerical codes are not necessarily portable across platforms.
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string.dump (function)
Returns a string containing a binary representation of the given function, so that a later loadstring on this string returns a copy of the function. function must be a Lua function without upvalues.
5. Standard libraries
Start from the beginning
