On 10/20/2012 12:53 AM, timotheecour wrote:
short version:
how to call a (non extern-C) function from visualD's debugger? ( I can
do it with extern C)
how to call a function with arguments that are stack variables (I can do
it with actual numeric values, eg actual pointer addresses)
long version:
when debugging a session inside visual D, it can be very useful to call
functions directly, eg:
* to print variables that visual D doesn't display properly (such as
dynamic arrays, where visualD just prints the length and pointer)
* for interactive purposes (eg trying a function with different parameters)
Currently, visualD's support for this is limited, but I was able to do
certain useful things (I'm not sure if many people realized one can do
this in visuald, but this can be useful):
I know it's possible and I use it in C++ from time to time, but never
tried it in D.
suppose we compile a D program into Main.exe:
we can call extern(C) functions as follows, by adding a watch variable
in visual studio debugger and entering in the name field:
Main.exe!main_test@test1(2)
=> will show value=25, type=int, and will print in the command prompt
"res=25"
now get address of z1 by looking into "Locals":
it shows:
- z1 {length=4 ptr=0x01f20f40 {1} } int[]
then display the dynamic array z1:
Main.exe!main_test@writelnPtr(3,0x01f20f40)
This is nice but not very convenient. Is there a way (if not, can that
be addressed in the near future) to support the following?
VS2012 allows "main_test@writelnPtr(z1.length,z1.ptr)"
Actually, the changes to autoexp.dat that are done by the installer are
supposed to display dynamic and associative arrays, but it seems they
are broken in VS2012 and maybe also 2010.
* Main.exe!main_test@writeln2(z1)
=>currently returns: identifier "z1" is undefined
VS2012 says: "Passing class, struct or union types by value to a
function evaluation is not supported". It works if you pass the argument
by reference.
* Main.exe!main_test@writeln2([1,2,3])
=>currently returns: expected a type specifier
The VS debugger expects C/C++ syntax, so it cannot do this.
* Main.exe!main_test@writeln3()
=>currently returns: identifier "main_test@writeln3" is undefined
If you disable name demangling by cv2pdb, the symbol
_D9main_test8writeln3FZv resolves to the function writeln3, but
unfortunately its type is reported as "void*". I guess the VS debugger
does not allow the calling convention used by D in function evaluation.
If you use mago as the debug engine, you will get better D expression
support and output, but it is not capable of running functions through
watch expressions. Unfortunately development of mago seems to have
stopped/paused. Nevertheless, I think a dedicated debug engine is the
way to go for the best user experience.
