Standard Libraries

Standard Libraries:

6 – Standard Libraries

The standard Lua libraries provide useful functions that are implemented directly through the C API. Some of these functions provide essential services to the language (e.g., type and getmetatable); others provide access to "outside" services (e.g., I/O); and others could be implemented in Lua itself, but are quite useful or have critical performance requirements that deserve an implementation in C (e.g., table.sort).

All libraries are implemented through the official C API and are provided as separate C modules. Currently, Lua has the following standard libraries:

basic library (§6.1);
coroutine library (§6.2);
package library (§6.3);
string manipulation (§6.4);
basic UTF-8 support (§6.5);
table manipulation (§6.6);
mathematical functions (§6.7) (sin, log, etc.);
input and output (§6.8);
operating system facilities (§6.9);
debug facilities (§6.10).

Except for the basic and the package libraries, each library provides all its functions as fields of a global table or as methods of its objects.

To have access to these libraries, the C host program should call the luaL_openlibs function, which opens all standard libraries. Alternatively, the host program can open them individually by using luaL_requiref to call luaopen_base (for the basic library), luaopen_package (for the package library), luaopen_coroutine (for the coroutine library), luaopen_string (for the string library), luaopen_utf8 (for the UTF8 library), luaopen_table (for the table library), luaopen_math (for the mathematical library), luaopen_io (for the I/O library), luaopen_os (for the operating system library), and luaopen_debug (for the debug library). These functions are declared in lualib.h.

Links:

https://www.lua.org/manual/5.3/manual.html#6

os.rename()

References/Lua/Lua/Standard Libraries/Operating System Facilities

os.rename (oldname, newname) Renames the file or directory named oldname to newname. If this function fails, it returns nil, plus a string describing

2025-01-10 15:47:30

io.close()

References/Lua/Lua/Standard Libraries/Input and Output Facilities

io.close ([file]) Equivalent to file:close(). Without a file, closes the default output file.

2025-01-10 15:47:30

select()

References/Lua/Lua/Standard Libraries/Basic Functions

select (index, ···) If index is a number, returns all arguments after argument number index; a negative number indexes from the end (-1 is the last argument)

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file:read()

References/Lua/Lua/Standard Libraries/Input and Output Facilities

file:read (···) Reads the file file, according to the given formats, which specify what to read. For each format, the function returns a string or a number with the

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file:flush()

References/Lua/Lua/Standard Libraries/Input and Output Facilities

file:flush () Saves any written data to file.

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os.execute()

References/Lua/Lua/Standard Libraries/Operating System Facilities

os.execute ([command]) This function is equivalent to the ISO C function system. It passes command to be executed by an operating system shell. Its first

2025-01-10 15:47:30

rawequal()