// vim:set ts=4 sw=4 ai et:
#include <stdio.h>
#include <execinfo.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
/*

Compile with "-rdynamic" to include function names in the backtrace output

Example output:

$ gcc -rdynamic -Werror assert-backtrace.c && ./a.out
Backtrace:

   1   a.out(quux+0x9) [0x55d540c74cd4]
   2   a.out(qux+0xe) [0x55d540c74d08]
   3   a.out(baz+0xe) [0x55d540c74d19]
   4   a.out(bar+0xe) [0x55d540c74d2a]
   5   a.out(foo+0xe) [0x55d540c74d3b]
   6   a.out(main+0x19) [0x55d540c74d57]
   7   /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7) [0x7fdc6b424b97]
   8   a.out(_start+0x2a) [0x55d540c74a5a]

a.out: assert-backtrace.c:57: quux: Assertion `0 && "test assertion" || printbt()' failed.
Aborted (core dumped)

*/

#define assert_bt(...) assert(__VA_ARGS__ || printbt())
#define STACK_DEPTH   20
int printbt(void)
{
    void *buffer[STACK_DEPTH];
    char **strings;
    int size, i;

    size = backtrace(buffer, STACK_DEPTH);
    strings = backtrace_symbols(buffer, size);

    fprintf(stderr, "Backtrace:\n\n");

    for (i = 1; i < size; i++) {
        if (strings[i][0] == '.' && strings[i][1] == '/')
            strings[i] += 2;

        fprintf(stderr, " %3d   %s\n", i, strings[i]);
    }

    fprintf(stderr, "\n");

    return 0;
}

void quux() { assert_bt(0 && "test assertion"); }
void qux() { quux(); }
void baz() { qux(); }
void bar() { baz(); }
void foo() { bar(); }

int main(int argc, char **argv)
{
    foo();
    return 0;
}