debug¶
This library provides functions useful for debugging and profiling code.
Nova note: A restricted debug library is registered; some stock Lua debug APIs are unavailable.
Description¶
Provides a few basic functions for debugging code in Roblox. Unlike the debug library found in Lua natively, this version has been heavily sandboxed.
Functions¶
traceback Partial Returns a string of undefined format that describes the current function call stack.
Returns a string of undefined format that describes the current function call stack.
Returns a traceback of the current function call stack as a string; in other words, a description of the functions that have been called up to this point. During debugging, this behaves like an error stack trace but does not stop execution of the script.
The level parameter specifies what level of the call stack to consider,
with 1 being the call of debug.traceback() itself, 2 being
the call of the function calling debug.traceback(), and so on.
See the code sample below for an example of sequential function calls.
Note that this function will often return inaccurate results (compared to the original source code) and that the format of the returned traceback may change at any time. You should not parse the return value for specific information such as script names or line numbers.
The following example includes sequential function calls; fnB() is
called, and it calls fnA() which then calls debug.traceback().
traceback Partial Returns a string of undefined format that describes the current function call stack.
Returns a string of undefined format that describes the current function call stack.
Returns a traceback of the current function call stack as a string; in other words, a description of the functions that have been called up to this point. During debugging, this behaves like an error stack trace but does not stop execution of the script.
The level parameter specifies what level of the call stack to consider,
with 1 being the call of debug.traceback() itself, 2 being
the call of the function calling debug.traceback(), and so on.
See the code sample below for an example of sequential function calls.
Note that this function will often return inaccurate results (compared to the original source code) and that the format of the returned traceback may change at any time. You should not parse the return value for specific information such as script names or line numbers.
The following example includes sequential function calls; fnB() is
called, and it calls fnA() which then calls debug.traceback().
info Partial Traverses the entire stack of current thread and returns a string containing the call stack of target level details.
Traverses the entire stack of current thread and returns a string containing the call stack of target level details.
Allows programmatic inspection of the call stack. This function differs from debug.traceback() in that it guarantees the format of the data it returns. This is useful for general logging and filtering purposes as well as for sending the data to systems expecting structured input, such as crash aggregation.
local function fnA()
-- Output source identifier ("s") and line ("l") at levels 1 and 2
print(debug.info(1, "sl")) --> fnA() 3
print(debug.info(2, "sl")) --> fnA() 7
end
fnA()
Note that this function is similar to debug.getinfo, an unavailable part of the standard Lua library which serves a similar purpose.
info Partial Traverses the entire stack of current thread and returns a string containing the call stack of target function details.
Traverses the entire stack of current thread and returns a string containing the call stack of target function details.
Allows programmatic inspection of the call stack. This function differs from debug.traceback() in that it guarantees the format of the data it returns. This is useful for general logging and filtering purposes as well as for sending the data to systems expecting structured input, such as crash aggregation.
local function fnA()
end
local function fnB()
end
-- Output line ("l"), name ("n"), and identifier ("f") for both fnA() and fnB()
print(debug.info(fnA, "lnf")) --> 1 fnA function: 0x75e3d3c398a81252
print(debug.info(fnB, "lnf")) --> 5 fnB function: 0x6022a6dc5ccf4ab2
Note that this function is similar to debug.getinfo, an unavailable part of the standard Lua library which serves a similar purpose.
info Partial Traverses the entire stack of target thread and returns a string containing the call stack of target level details.
Traverses the entire stack of target thread and returns a string containing the call stack of target level details.
Allows programmatic inspection of the call stack. This function differs from debug.traceback() in that it guarantees the format of the data it returns. This is useful for general logging and filtering purposes as well as for sending the data to systems expecting structured input, such as crash aggregation.
local function fnA()
-- Output source identifier ("s") and line ("l") at levels 1 and 2
print(debug.info(1, "sl")) --> fnA() 3
print(debug.info(2, "sl")) --> fnA() 7
end
fnA()
Note that this function is similar to debug.getinfo, an unavailable part of the standard Lua library which serves a similar purpose.
profilebegin Not yet Starts profiling for a label.
Starts profiling for a label.
Starts profiling for a MicroProfiler label.
profileend Not yet Stops profiling for the most recent label that debug.profilebegin() opened.
Stops profiling for the most recent label that debug.profilebegin() opened.
Stops profiling for the most recent MicroProfiler label that debug.profilebegin() opened.
getmemorycategory Not yet Returns the name of the current thread's active memory category.
Returns the name of the current thread's active memory category.
setmemorycategory Not yet Assigns a custom tag to the current thread's memory category.
Assigns a custom tag to the current thread's memory category.
Assigns a custom tag name to the current thread's memory category in the Developer Console. Useful for analyzing memory usage of multiple threads in the same script which would otherwise be grouped together under the same tag/name. Returns the name of the current thread's previous memory category.
resetmemorycategory Not yet Resets the tag assigned by debug.setmemorycategory() to the automatically assigned value (typically, the script name).
Resets the tag assigned by debug.setmemorycategory() to the automatically assigned value (typically, the script name).
dumpcodesize Not yet Displays a table of native code size of individual functions and scripts.
Displays a table of native code size of individual functions and scripts. This function is only available in the Command Bar in Studio. More details can be found on the Native Code Generation page.
Roblox reference: debug