demo of using Zig's standard library from C code

debug.zig

const std = @import("std");
const builtin = @import("builtin");

export fn captureStackTrace(addresses: [*]usize, len: usize, first_addr: usize) void {
    var trace = builtin.StackTrace{
        .instruction_addresses = addresses[0..len],
        .index = 0,
    };
    std.debug.captureStackTrace(if (first_addr == 0) null else first_addr, &trace);
}

export fn dumpStackTrace(addresses: [*]usize, len: usize) void {
    var index: usize = 0;
    while (index < len and addresses[index] != 0) {
        index += 1;
    }
    var trace = builtin.StackTrace{
        .instruction_addresses = addresses[0..len],
        .index = index,
    };
    std.debug.dumpStackTrace(trace);
}

output.txt

$ zig build-lib debug.zig --library c
$ zig build-exe --c-source test.c --object libdebug.a --library c
$ ./test
/home/andy/tmp/abc/debug.zig:9:32: 0x203329 in ??? (debug)
    std.debug.captureStackTrace(if (first_addr == 0) null else first_addr, &trace);
                               ^
/home/andy/tmp/abc/test.c:7:5: 0x203099 in ??? (test.c)
    captureStackTrace(&addresses[0], STACK_N, 0);
    ^
/home/andy/tmp/abc/test.c:14:5: 0x203050 in ??? (test.c)
    foo();
    ^
???:?:?: 0x7fcbf9879b5e in ??? (???)

test.c

#include "debug.h"

#define STACK_N 4
uintptr_t addresses[STACK_N];

static void foo(void) {
    captureStackTrace(&addresses[0], STACK_N, 0);
}

static void bar(void) {}

int main(int argc, char **argv) {
    bar();
    foo();
    dumpStackTrace(addresses, STACK_N);
    return 0;
}