• Bottled Genie (15/15) May 15 2016 Hello All
• Bottled Genie (16/16) May 16 2016 To be specific, I am trying to get an automatic backtrace
• Bottled Genie (5/5) May 17 2016 Can someone help me?
• Joakim (6/11) May 17 2016 There is a problem in druntime with @nogc and nothrow not

Bottled Genie <Genie Bottle.com> writes:

Hello All

I am trying to make use of function signal from module 
core.stdc.signal.

The function needs a function pointer as an argument and since 
signal has been marked with attributes  nogc and nothrow, the 
function I pass to it as an argument also has to be nothrow and 
 nogc. Are these attributes intended on signal? If yes, how does 
it help.

Why should C functions in core.stdc be marked nothrow and  nogc? 
And how do I overcome the restriction imposed on function pointer 
that I want to pass to signal? In my case the function I want to 
pass as argument to signal is actually not  nogc nothrow. What 
should I do?

Regards
- Genie

Bottled Genie <Genie Bottle.com> writes:

To be specific, I am trying to get an automatic backtrace 
generated for my d application in case of segfaults, using the 
technique shown in the following link:

http://stackoverflow.com/a/77336

Going by the code snippet in the link I have to pass a pointer to 
function handler as an argument to signal. And signal having 
being declared as  nogc nothrow expects handler to have the same 
attributes.

But handler calls backtrace and backtrace_symbols_fd which are 
declared in module core.sys.linux.execinfo and do not have  nogc 
attribute, thus making it impossible for me to specify  nogc with 
the handler function.

I believe the solution lies in adding  nogc for all the functions 
in execinfo module. Am I missing something?

Regards
- Genie

Bottled Genie <Genie Bottle.com> writes:

Can someone help me?

How can I call core.sys.linux.execinfo:backtrace from a 
core.stdc.signal: signal handler? The problem is that signal has 
been declared with  nogc in druntime and backtrace does not have 
that attribute.

Joakim <dlang joakim.fea.st> writes:

On Tuesday, 17 May 2016 at 09:24:50 UTC, Bottled Genie wrote:
 Can someone help me?

 How can I call core.sys.linux.execinfo:backtrace from a 
 core.stdc.signal: signal handler? The problem is that signal 
 has been declared with  nogc in druntime and backtrace does not 
 have that attribute.

There is a problem in druntime with  nogc and nothrow not 
covering all the C declarations they should.  If you're 
comfortable with writing up a PR to fix this issue, it'll most 
likely be merged:

http://wiki.dlang.org/Starting_as_a_Contributor