Subj : Re: pthreads (linux) questions
To   : comp.programming.threads
From : Christian Parpart
Date : Sun Aug 21 2005 12:31 pm

jacob navia wrote:

> Joe Seigh wrote:
> 
>   > Threads don't have pids any more.  What non standard non portable
>> thing are you trying to do?
>> 
> 
> I want to print the stack of an application when it crashes.

no need for all you did before. 
The following works in pthread environments:

#include <execinfo.h>
#include <cxxabi.h>      // in case you're using c++
#include <dlfcn.h>

void getCallTrace(int skipFrames /* = 0 */) {
    void *trace[1024];

    int traceCount = backtrace(trace, 1024);

    for (int i = skipFrames; i < traceCount; ++i) {
        char *sname = NULL;
        Dl_info info;

        if (dladdr(stack[i], &info) != 0) {
#if __cplusplus
            char *buf = NULL;
            int len = 0;
            int status = 0;
            sname = abi::__cxa_demangle(info.dli_sname, buf, &len, &status);
#else
            sname = info.dli_sname;
#endif
        }

        fprintf(stderr, "[%02d] @%08X %s\n", i, trace[i], sname);
    }
}

this is considered PSEUDO-code, as I just wrote it on-the-fly.

A working code (C++) is at [1].

> Apparently there is no documentation isn't it?

I recomment you in having a look at the info-pages of backtrace(),
and the man-pages of dladdr();

> Again:
> Under 32 bits I used those symbols in the pthread library
> to get info about the running threads.
> I would attach to each thread in turn, and using ptrace I would read
> their descriptors, what allowed me to print the state of each
> thread at the moment of the crash.
> 
> How do I do that under 64 bits?

never played around with ptrace(), but maybe my above snippet 
will help you anyway.

Regards,
Christian Parpart.

[1] http://swl.trapni-akane.org/browser/trunk/Core/src/System/Diagnostics/TStackFrame.unix.cpp

.