CODEWITHSUNDEEP
c++linuxdebugging
chikadance
chikadance

Reputation: 4167

addr2line get line number always return 0

I use following code to get backtrace

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);
    for (i = 1; i < bt_size; i++) {
        size_t len = strlen(bt_syms[i]);
        std::cout << bt_syms[i] << std::endl;
    }
    free(bt_syms);
}


int main() {
    print_backtrace();
    return 0;
}

and the output is:

/home/roroco/Dropbox/c/ro-c/cmake-build-debug/ex/test_backtrace_with_line_number
/home/roroco/Dropbox/c/ro-c/cmake-build-debug/ex/test_backtrace_with_line_number(main+0x9) [0x400d0b]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0) [0x7ff20985c830]
/home/roroco/Dropbox/c/ro-c/cmake-build-debug/ex/test_backtrace_with_line_number(_start+0x29) [0x400b29]

when i use addr2line to convert addr to line number with following, the return always "??:0", how to get real line number?

roroco@roroco ~/Dropbox/c/ro-c $ addr2line -e /home/roroco/Dropbox/c/ro-c/cmake-build-debug/CMakeFiles/3.12.0/CompilerIdCXX/a.out 0x400d0b
??:0
roroco@roroco ~/Dropbox/c/ro-c $ addr2line -e /home/roroco/Dropbox/c/ro-c/cmake-build-debug/CMakeFiles/3.12.0/CompilerIdCXX/a.out 0x7ff20985c830
??:0
roroco@roroco ~/Dropbox/c/ro-c $ addr2line -e /home/roroco/Dropbox/c/ro-c/cmake-build-debug/CMakeFiles/3.12.0/CompilerIdCXX/a.out 0x400b29
??:0

Upvotes: 2

Views: 1236

Answers (1)

J-Christophe
J-Christophe

Reputation: 2070

It turns out that 

/home/roroco/Dropbox/c/ro-c/cmake-build-debug/CMakeFiles/3.12.0/CompilerIdCXX/a.out

is not the executable you built (it corresponds to the compiler test done by CMake).

Instead you could try the following:

addr2line -e /home/roroco/Dropbox/c/ro-c/cmake-build-debug/ex/test_backtrace_with_line_number

where test_backtrace_with_line_number corresponds to the executable you built. It should be the name associated with the add_executable command in your CMakeLists.txt

Upvotes: 1

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