How to make backtrace()/backtrace_symbols() print the function names?

user_613821 0
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The Linux specific backtrace() and backtrace_symbols() allows you to produce a call trace of the program. However, it only prints function addresses, not their names for my program. How can I make them print the function names as well ? I've tried compiling the program with -g as well as -ggdb. The test case below just prints this:


    BACKTRACE ------------
    ./a.out() [0x8048616]
    ./a.out() [0x8048623]
    /lib/libc.so.6(__libc_start_main+0xf3) [0x4a937413]
    ./a.out() [0x8048421]
    ----------------------

I'd want the first 2 items to also show the function names, foo and main

Code:

#include <execinfo.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>

static void full_write(int fd, const char *buf, size_t len)
{
        while (len > 0) {
                ssize_t ret = write(fd, buf, len);

                if ((ret == -1) && (errno != EINTR))
                        break;

                buf += (size_t) ret;
                len -= (size_t) ret;
        }
}

void print_backtrace(void)
{
        static const char start[] = "BACKTRACE ------------\n";
        static const char end[] = "----------------------\n";

        void *bt[1024];
        int bt_size;
        char **bt_syms;
        int i;

        bt_size = backtrace(bt, 1024);
        bt_syms = backtrace_symbols(bt, bt_size);
        full_write(STDERR_FILENO, start, strlen(start));
        for (i = 1; i < bt_size; i++) {
                size_t len = strlen(bt_syms[i]);
                full_write(STDERR_FILENO, bt_syms[i], len);
                full_write(STDERR_FILENO, "\n", 1);
        }
        full_write(STDERR_FILENO, end, strlen(end));
    free(bt_syms);
}
void foo()
{
    print_backtrace();
}

int main()
{
    foo();
    return 0;
}
backtrace linux c debugging
5 Answers

the answer on the top has a bug if ret == -1 and errno is EINTER you should try again, but not count ret as copied (not going to make an account just for this, if you don't like it tough)

static void full_write(int fd, const char *buf, size_t len)
{
        while (len > 0) {
                ssize_t ret = write(fd, buf, len);

                if ((ret == -1) {
                        if (errno != EINTR))
                                break;
                        //else
                        continue;
                }
                buf += (size_t) ret;
                len -= (size_t) ret;
        }
}
user_89535180

Boost backtrace

Very convenient because it prints both:

  • unmangled C++ function names
  • line numbers

automatically for you.

Usage summary:

#define BOOST_STACKTRACE_USE_ADDR2LINE
#include <boost/stacktrace.hpp>

std::cout << boost::stacktrace::stacktrace() << std::endl;

I have provided a minimal runnable example for it and many other methods at: print call stack in C or C++

user_8952450
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