Seems not relevant to some questions with similar titles.
//some other code
std::string s = Lookup->getName().str();
-> break here //some other code
Note: "Lookup" is clang::DirectoryLookup http://clang.llvm.org/doxygen/classclang_1_1DirectoryLookup.html, "Lookup->getName()" is llvm::StringRef http://llvm.org/doxygen/classllvm_1_1StringRef.html.
When break at the above place, in the "Watch" pane in VS2017, the string variable "s" is initialized successfully and its value can be shown in "Watch" pane.
But when try to show(watch) the expression "Lookup->getName().str()" which is just how "s" is initialized, it says:
Lookup->getName().str() | Function llvm::StringRef::str has no address, possibly due to compiler optimizations.
the source code of StringRef::str() is:
/// str - Get the contents as an std::string.
LLVM_NODISCARD
std::string str() const {
if (!Data) return std::string();
return std::string(Data, Length);
}
And all the libraries is in debug version. Based on the above fact, there seems to be no reason for this to happen.
Such thing happens in other situations during debuging a Clang Libtooling program and it make debugging very hard.
What is the possible reason and how to solve it?
I tried #user15331850 solution and it didn't help, but setting Linker-> Debugging-> Generate Debug Info to "/DEBUG:FULL" seems giving me all variables now.
This may be due to optimization option is enabled.
You can disable the same by following these steps:
Right click on the solution
Click on the "properties"
From the left pane, click on the "Configuration Properties"
Click on "C/C++" from the sub-option
Then click on the "optimization" and select "Disabled(/Od)" from the list
That's it. Hope it works for you!!
I had this issue. I needed to change the settings for: Linker-> Debugging-> Generate Debug Info from "/DEBUG:FASTLINK" to "/DEBUG".
Is there any way to change value of variable to on a conditional breakpoint and continue execution.
My code is like this
switch(var){ //conditional breakpoint on this line
case 1:
break;
...
}
I put conditional breakpoint like below
(var == 0 ) || (var ==1) is true
So when this breakpoint hits, I want to change var = 2, and continue execution.
What I found: I found Action also, but it only log messages. Is there any way to executing a statement like var = 2 as Action taken on this conditional breakpoint.
I don't want to change code because building it takes hell lot of time.
Note: I am working C++ on Visual studio 2015
In Log a message to Output Window write {my_variable=12345} the side effect of log output is assigning 12345 to my_variable.
Take into account that Log a message can accept and evaluate complex expressions in curly braces.
You can modify a variable directly in memory to change the execution flow through a quick watch (Shift+F9) or watch window in Visual Studio.
Make sure that in Tools / Options / Debugging you have the "Enable Edit and Continue" Enabled/Checked and then you will be able to edit your code while debugging and continue without the need to rebuild or to stop execution.
More information can be found in How to: Enable and Disable Edit and Continue
This used to work, I can't seem to get it to work now. Worked excellent on loops and also good for altering values without altering the source or the code (and accidently committing it).
Conditional break point, break if true
(url = "http://localhost:1234/") != url
This works thanks to assignment always returns it's assigned value. This will never be true as url becomes localhost
Configuration:
Eclipse Luna, debugging a C++ code with gcc.
Question:
Consider the code below, where I set the break point:
myFunction( someString.c_str() ); // << Break point is here
I want step-into directly to the myFunction, ignore the 'c_str()' call
Note: I am trying to avoid the obvious solution, which is to put a break point inside the the myFunction call.
This is what to do when the debugger hits the main line:
Hit 'F5: Step Into'
The debugger step into the 'c_str()' method. (You may not want that).
Hit 'F7 - Step Return'
The debugger will exit 'c_str()' and return to the entry point of the 'myFunction' call.
Hit 'F5 Step Into'
Now the debugger will go into the 'myFunction' call
I often need to find out which functions are getting called in a C++ file. I am using Eclipse 3.7.0. The C++ file may be huge. I want to write a plugin which will detect the beginning of a function and insert a
std::cout << "Function Name called !!" << std::endl
at the beginning in the code editor window. I think eclipse already detects functions since it does display the entire file structure in the Outline view. I would like to use this information to inject the cout statements. The 'Function Name' part should be replaced by the actual function name in the definition part of the function.
Is this even possible ? Where would I start ?
It would be even more awesome if I could insert couts automatically into all functions which call a particular function(say the one the cursor is in).
I'm debugging an application (C++), and I've found a point in the code where I want to change a value (via the debugger). So right now, I've got a breakpoint set, whereupon I do:
Debugger reaches breakpoint
I modify the variable I want to change
I hit F5 to continue running
lather, rinse, repeat
It's hitting this breakpoint a lot, so I would like to automate this. I would like to set the Breakpoint to run a macro, and continue execution.
However, I have no experience writing VisualStudio macros, so I don't know the commands for modifying a variable of the executing program. I've looked around, but haven't found anything helpful online so far.
I found how to do this with a macro. Initially, I tried using Ctrl-Shift-R to record a macro of keystrokes, but it stopped recording when I did Ctrl-Alt-Q. But I was able to edit the macro to get it to work. So here's what I did, in case anyone else wants to do something similar.
Tools -> Macros -> Macro Explorer
Right Click -> New macro
Public Module RecordingModule
Sub setvalue()
DTE.Debugger.ExecuteStatement("variable_name=0")
End Sub
End Module
This macro will execute the assignment statement, setting my variable (in this case, making it a NULL pointer).
Right Click on a BreakPoint -> When Hit...
Check "Run a macro"
Select Macros.MyMacros.RecordingModule.setvalue
Check "Continue execution"
Click OK
Then, I was able to run my program, automatically adjusting a pointer to NULL as it went. This was very useful for testing, and did not require recompiling.
Looking for similar today and found that you can also use the 'Print a message:' option instead of a macro. Values from code can be printed by placing them inside {}. The key is that VS will also evaluate the content as an expression - so {variable_name=0} should achieve the same as the macro example.
If you are think of a macro in the same way as Microsoft excel, then you're out of luck. It doesn't quite work that way.
In C++, a macro refers to a small inline function created with #define. It is a preprocessor, so a macro is like using a replace on all its references with its body.
For example:
#define add(a,b) ((a)+(b))
int main() {
int a=3, b=4, c=5, d=6, e, f;
d = add(a,b);
e = add(c,d);
}
Would like to the c++ compiler as:
int main() {
int a=3, b=4, c=5, ...;
d = ((a)+(b));
e = ((c)+(d));
}
Now, back to your question. If the variable is within scope at this breakpoint, just set it from within your code:
myVar = myValue;
If it is not, but it is guaranteed to exist, you may need a little hack. Say that this variable is an int, make a global int pointer. If this variable is static, make sure to set it to its address, and back to NULL inside it's scope. If it is dynamic, you may need some extra work. Here is an example:
int* globalIntPointer;
void func() {
*globalIntPointer = 3;
//...
}
int main() {
int a = 5;
globalIntPointer = &a;
func();
//...
globalIntPointer = NULL; // for safety sake
return 0;
}
You can execute a VS macro when a breakpoint is hit (open the breakpoints window, right click on the breakpoint in question, and select "When Hit..." off the popup menu). I'm less certain about writing a macro that modifies a variable of the program under debug though -- I've never done that, and a quick try with attempting to record a macro to do it doesn't seem to work (all it records is activating the right window, not changing the value).
Select "Condition..." and write an assignment for the variable in question in the "Condition:" textbox. This will naturally resolve to "true" with it not being an actual conditional test. Therefore, the breakpoint is never hit, and your variable has been set accordingly.