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int(3erl) | Erlang Module Definition | int(3erl) |
NAME¶
int - Interpreter Interface.DESCRIPTION¶
The Erlang interpreter provides mechanisms for breakpoints and stepwise execution of code. It is primarily intended to be used by Debugger, see the User's Guide and debugger(3erl). The following can be done from the shell:- *
- Specify the modules to be interpreted.
- *
- Specify breakpoints.
- *
- Monitor the current status of all processes executing code in interpreted modules, also processes at other Erlang nodes.
BREAKPOINTS¶
Breakpoints are specified on a line basis. When a process executing code in an interpreted module reaches a breakpoint, it stops. This means that a breakpoint must be set at an executable line, that is, a code line containing an executable expression. A breakpoint has the following:- *
- A status, which is active or inactive. An inactive breakpoint is ignored.
- *
- A trigger action. When a breakpoint is reached, the trigger action specifies if the breakpoint is to continue as active ( enable), or to become inactive ( disable), or to be removed (delete).
- *
- Optionally an associated condition. A condition is a tuple {Module,Name}. When the breakpoint is reached, Module:Name(Bindings) is called. If it evaluates to true, execution stops. If it evaluates to false, the breakpoint is ignored. Bindings contains the current variable bindings. To retrieve the value for a specified variable, use get_binding.
EXPORTS¶
i(AbsModule) -> {module,Module} | error
Types:
AbsModules = [AbsModule]
AbsModule = Module | File | [Module | File]
Module = atom()
File = string()
Module = atom()
File = string()
Interprets the specified module(s). i/1 interprets the module only at the
current node. ni/1 interprets the module at all known nodes.
A module can be specified by its module name (atom) or filename.
If specified by its module name, the object code Module.beam is searched
for in the current path. The source code Module.erl is searched for
first in the same directory as the object code, then in an src
directory next to it.
If specified by its filename, the filename can include a path and the
.erl extension can be omitted. The object code Module.beam is
searched for first in the same directory as the source code, then in an
ebin directory next to it, and then in the current path.
n(AbsModule) -> ok
Note:
The interpreter requires both the source code and the object code. The object
code must include debug information, that is, only modules compiled
with option debug_info set can be interpreted.
The functions returns {module,Module} if the module was interpreted,
otherwise error is returned.
The argument can also be a list of modules or filenames, in which case the
function tries to interpret each module as specified earlier. The function
then always returns ok, but prints some information to stdout if
a module cannot be interpreted.
Types:
AbsModule = Module | File | [Module | File]
Module = atom()
File = string()
Module = atom()
File = string()
Stops interpreting the specified module. n/1 stops interpreting the
module only at the current node. nn/1 stops interpreting the module at
all known nodes.
As for i/1 and ni/1, a module can be specified by its module name
or filename.
interpreted() -> [Module]
Types:
Module = atom()
Returns a list with all interpreted modules.
file(Module) -> File | {error,not_loaded}
Types:
Module = atom()
File = string()
Returns the source code filename File for an interpreted module
Module.
interpretable(AbsModule) -> true | {error,Reason}
Types:
AbsModule = Module | File
Module = atom()
File = string()
Reason = no_src | no_beam | no_debug_info | badarg | {app,App}
App = atom()
Module = atom()
File = string()
App = atom()
Checks if a module can be interpreted. The module can be specified by its module
name Module or its source filename File. If specified by a
module name, the module is searched for in the code path.
The function returns true if all of the following apply:
The function returns {error,Reason} if the module cannot be interpreted.
Reason can have the following values:
Notice that the function can return true for a module that in fact is not
interpretable in the case where the module is marked as sticky or resides in a
directory marked as sticky. The reason is that this is not discovered until
the interpreter tries to load the module.
auto_attach() -> false | {Flags,Function}
- *
- Both source code and object code for the module is found.
- *
- The module has been compiled with option debug_info set.
- *
- The module does not belong to any of the applications Kernel, STDLIB, GS, or Debugger.
- no_src:
- No source code is found. It is assumed that the source code and object code are located either in the same directory, or in src and ebin directories next to each other.
- no_beam:
- No object code is found. It is assumed that the source code and object code are located either in the same directory, or in src and ebin directories next to each other.
- no_debug_info:
- The module has not been compiled with option debug_info set.
- badarg:
- AbsModule is not found. This could be because the specified file does not exist, or because code:which/1 does not return a BEAM filename, which is the case not only for non-existing modules but also for modules that are preloaded or cover-compiled.
- {app,App}:
- App is kernel, stdlib, gs, or debugger if AbsModule belongs to one of these applications.
Types:
Flags = [init | break | exit]
Function = {Module,Name,Args}
Module = Name = atom()
Args = [term()]
Module = Name = atom()
Args = [term()]
Gets and sets when and how to attach automatically to a process executing code
in interpreted modules. false means never attach automatically, this is
the default. Otherwise automatic attach is defined by a list of flags and a
function. The following flags can be specified:
When the specified event occurs, the function Function is called as:
stack_trace() -> Flag
- *
- init - Attach when a process for the first time calls an interpreted function.
- *
- break - Attach whenever a process reaches a breakpoint.
- *
- exit - Attach when a process terminates.
spawn(Module, Name, [Pid | Args])Pid is the pid of the process executing interpreted code.
Types:
Flag = all | no_tail | false
Gets and sets how to save call frames in the stack. Saving call frames makes it
possible to inspect the call chain of a process, and is also used to emulate
the stack trace if an error (an exception of class error) occurs. The
following flags can be specified:
break(Module, Line) -> ok | {error,break_exists}
- all:
- Save information about all current calls, that is, function calls that have not yet returned a value.
- no_tail:
- Save information about current calls, but discard previous information when a tail recursive call is made. This option consumes less memory and can be necessary to use for processes with long lifetimes and many tail recursive calls. This is the default.
- false:
- Save no information about currentcalls.
Types:
Module = atom()
Line = int()
Creates a breakpoint at Line in Module.
delete_break(Module, Line) -> ok
Types:
Module = atom()
Line = int()
Deletes the breakpoint at Line in Module.
break_in(Module, Name, Arity) -> ok | {error,function_not_found}
Types:
Module = Name = atom()
Arity = int()
Creates a breakpoint at the first line of every clause of function
Module:Name/Arity.
del_break_in(Module, Name, Arity) -> ok | {error,function_not_found}
Types:
Module = Name = atom()
Arity = int()
Deletes the breakpoints at the first line of every clause of function
Module:Name/Arity.
no_break() -> ok
Deletes all breakpoints, or all breakpoints in Module.
disable_break(Module, Line) -> ok
Types:
Module = atom()
Line = int()
Makes the breakpoint at Line in Module inactive.
enable_break(Module, Line) -> ok
Types:
Module = atom()
Line = int()
Makes the breakpoint at Line in Module active.
action_at_break(Module, Line, Action) -> ok
Types:
Module = atom()
Line = int()
Action = enable | disable | delete
Sets the trigger action of the breakpoint at Line in Module to
Action.
test_at_break(Module, Line, Function) -> ok
Types:
Module = atom()
Line = int()
Function = {Module,Name}
Name = atom()
Name = atom()
Sets the conditional test of the breakpoint at Line in Module to
Function. The function must fulfill the requirements specified in
section Breakpoints.
get_binding(Var, Bindings) -> {value,Value} | unbound
Types:
Var = atom()
Bindings = term()
Value = term()
Retrieves the binding of Var. This function is intended to be used by the
conditional function of a breakpoint.
all_breaks() -> [Break]
Types:
Break = {Point,Options}
Point = {Module,Line}
Module = atom()
Line = int()
Options = [Status,Trigger,null,Cond|]
Status = active | inactive
Trigger = enable | disable | delete
Cond = null | Function
Function = {Module,Name}
Name = atom()
Point = {Module,Line}
Module = atom()
Line = int()
Options = [Status,Trigger,null,Cond|]
Status = active | inactive
Trigger = enable | disable | delete
Cond = null | Function
Function = {Module,Name}
Name = atom()
Gets all breakpoints, or all breakpoints in Module.
snapshot() -> [Snapshot]
Types:
Snapshot = {Pid, Function, Status, Info}
Pid = pid()
Function = {Module,Name,Args}
Module = Name = atom()
Args = [term()]
Status = idle | running | waiting | break | exit | no_conn
Info = {} | {Module,Line} | ExitReason
Line = int()
ExitReason = term()
Pid = pid()
Function = {Module,Name,Args}
Module = Name = atom()
Args = [term()]
Status = idle | running | waiting | break | exit | no_conn
Info = {} | {Module,Line} | ExitReason
Line = int()
ExitReason = term()
Gets information about all processes executing interpreted code.
Status is one of the following:
clear() -> ok
- *
- Pid - Process identifier.
- *
- Function - First interpreted function called by the process.
- *
- Status - Current status of the process.
- *
- Info - More information.
- *
- idle - The process is no longer executing interpreted code. Info={}.
- *
- running - The process is running. Info={}.
- *
- waiting - The process is waiting at a receive. Info={}.
- *
- break - Process execution is stopped, normally at a breakpoint. Info={Module,Line}.
- *
- exit - The process is terminated. Info=ExitReason.
- *
- no_conn - The connection is down to the node where the process is running. Info={}.
Clears information about processes executing interpreted code by removing all
information about terminated processes.
continue(Pid) -> ok | {error,not_interpreted}
Types:
Pid = pid()
X = Y = Z = int()
Resumes process execution for Pid or c:pid(X,Y,Z).
debugger 4.2.1 | Ericsson AB |