aytey / backward-c

backward-c

backward-c

Purpose

backward-c is a limited, bare-bones C "port" of backward-cpp. Its purpose is to print a stack-trace to stderr, along with the corresponding source code (if it can be located) for each frame.

The code was heavily inspired by Maxim Egorushkin's C++ code for working with libdw.

Example

If your code is compiled with -g, then you should get something like this:

Source "/home/avj/clones/backward-c/main.c" line 20 in handler
        16   (void)sig;
        17
        18   /* show a backtrace */
    >   19   show_backtrace();
        20
        21   /* teardown our application */
        22   exit(1);
Object "" at 0x7f5e2037d52f in <unknown>
Source "/home/avj/clones/backward-c/crash.c" line 10 in crash
         6
         7 void crash() {
         8   int *p = NULL;
    >    9   *p = 10;
        10 }
        11
        12 // EOF
Source "/home/avj/clones/backward-c/main.c" line 36 in main
        32
        33 int main(void) {
        34   setup_handlers();
    >   35   crash();
        36   return 0;
        37 }
        38
Object "" at 0x7f5e20367b24 in __libc_start_main
Source "../sysdeps/x86_64/start.S" line 120 in _start

Usage

To use backward-c:

• add show_backtrace.o to your build system
• call show_backtrace from your code
• compile with -g
• link with -ldw -ldl -lunwind

Deficiencies when compared to backward-cpp

There are currently a few deficiencies when compared to backward-cpp:

• backward-c only supports libdw and libunwind
• backward-c does not show the name of a non-source file (e.g., if the source cannot be identified with libdw)
• backward-c does not support "skipping" of n inner frames

Pull requests are greatly welcomed to address any of the above!

Dependencies

• libdw-devel (openSUSE) / elfutils-devel (CentOS)
• libunwind-devel (openSUSE/CentOS)

License

This code is licensed under MIT