gdb does not stops inside a template function

gdb does not stops inside a template function

[Dima Sorkin]

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Hi.
 I have the following problem with gdb6.3 :
If I put a breakpoint on a line inside a function template,
the gdb not always stops there.

Please see attached ".cpp" file and the gdb session transcript
(file: "templ_dbg.1.output").
It can be seen that gdb stops on first call to "f",
but not on second.

Regards and thank you,
  Dima.

P.S.
 I use various versions of gcc compiler (3.3.6, 4.0.0),
the result was the same.

[-- Attachment #2: templ_dbg.lines_numbered.cpp --]
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1 // templ_dbg.cpp -*-c++-*-
2
3 template<typename T> T const f(T const &t){
4         return t+t;
5 }
6
7 #include<iostream>
8 using namespace std;
9
10 int main(){
11         int i(5);
12         cout << f(i) << '\n';
13
14         double d(0.3);
15         cout << f(d) << '\n';
16
17         return 0;
18 }
19


[-- Attachment #3: templ_dbg.1.output --]
[-- Type: text/plain, Size: 458 bytes --]

(gdb) break templ_dbg.cpp:4
Breakpoint 1 at 0x804870b: file templ_dbg.cpp, line 4.
(gdb) run
Starting program: /home/dima/templ_dbg 
Reading symbols from shared object read from target memory...done.
Loaded system supplied DSO at 0x50d000

Breakpoint 1, f<int> (t=@0xbfa784c4) at templ_dbg.cpp:4
4               return t+t;
(gdb) print t
$1 = (const int &) @0xbfa784c4: 5
(gdb) continue
Continuing.
10
0.6

Program exited normally.
(gdb)


[-- Attachment #4: gdb.version --]
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gdb does not stops inside a template function

[Nick Roberts]

> Hi.
>  I have the following problem with gdb6.3 :
> If I put a breakpoint on a line inside a function template,
> the gdb not always stops there.


> Please see attached ".cpp" file and the gdb session transcript
> (file: "templ_dbg.1.output").
> It can be seen that gdb stops on first call to "f",
> but not on second.

...
(gdb) break templ_dbg.cpp:4

I think you need to do:

(gdb) b int const f<int>(int const&)
(gdb) b double const f<double>(double const&)

if you want it to stop at both places.  Completion makes them easier
to type:

(gdb) b int<TAB>
(gdb) b double<TAB>

(Although I can only see how to select a candidate using Emacs.)

-- 
Nick                                           http://www.inet.net.nz/~nickrob

Re: gdb does not stops inside a template function

[Daniel Jacobowitz]

On Tue, Jun 20, 2006 at 10:38:01AM +0200, Dima Sorkin wrote:
> Hi.
> I have the following problem with gdb6.3 :
> If I put a breakpoint on a line inside a function template,
> the gdb not always stops there.
> 
> Please see attached ".cpp" file and the gdb session transcript
> (file: "templ_dbg.1.output").
> It can be seen that gdb stops on first call to "f",
> but not on second.

Yes, this is a known bug; it's basically the same bug as not stopping
in constructor functions using g++.  Sorry.  No one has had time to do
the major changes needed to fix it.

-- 
Daniel Jacobowitz
CodeSourcery