Cpptrace is a lightweight C++ stacktrace library supporting C++11 and greater on Linux, macOS, and Windows including MinGW and Cygwin environments. The goal: Make stack traces simple for once.

Some day C++23's <stacktrace> will be ubiquitous. And maybe one day the msvc implementation will be acceptable.

This library is in beta, if you run into any problems please open an issue!

• 30-Second Overview
  • CMake FetchContent Usage
• In-Depth Documentation
  • API
  • Notable Library Configurations
  • Notes About the Library and Future Work
  • Usage
    • CMake FetchContent
    • System-Wide Installation
    • Local User Installation
    • Package Managers
    • Platform Logistics
    • Static Linking
  • Library Internals
    • Summary of Library Configurations
  • Testing Methodology
• License

Generating traces is as easy as calling cpptrace::print_trace:

#include <cpptrace/cpptrace.hpp>

void trace() {
    cpptrace::generate_trace().print();
}

/* other stuff */

Cpptrace provides access to resolved stack traces as well as lightweight raw traces (just addresses) that can be resolved later:

const auto raw_trace = cpptrace::generate_raw_trace();
// then later
raw_trace.resolve().print();

Cpptrace also provides exception types that store stack traces:

#include <cpptrace/cpptrace.hpp>

void trace() {
    throw cpptrace::exception();
}

/* other stuff */
// terminate called after throwing an instance of 'cpptrace::exception'
//   what():  cpptrace::exception:
// Stack trace (most recent call first):
// #0 0x00005641c715a1b6 in trace() at demo.cpp:9
// #1 0x00005641c715a229 in foo(int) at demo.cpp:16
// #2 0x00005641c715a2ba in main at demo.cpp:34

include(FetchContent)
FetchContent_Declare(
  cpptrace
  GIT_REPOSITORY https://github.com/jeremy-rifkin/cpptrace.git
  GIT_TAG        v0.1.1 # <HASH or TAG>
)
FetchContent_MakeAvailable(cpptrace)
target_link_libraries(your_target cpptrace)

# On windows copy cpptrace.dll to the same directory as the executable for your_target
if(WIN32)
  add_custom_command(
    TARGET your_target POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E copy_if_different
    $<TARGET_FILE:cpptrace> $<TARGET_FILE_DIR:your_target>
  )
endif()

On windows and macos some extra work is required, see below.

cpptrace::generate_trace() can used to generate a stacktrace object at the current call site. Resolved frames can be accessed from this object with .frames and also the trace can be printed with .print(). Cpptrace also provides a method to get lightweight raw traces, which are just vectors of program counters, which can be resolved at a later time.

Note: Debug info (-g//Z7//Zi//DEBUG) is generally required for good trace information.

Note: Currently on Mac .dSYM files are required, which can be generated with dsymutil yourbinary. A cmake snippet for generating these is included above.

namespace cpptrace {
    /*
     * Raw trace access
     */
    struct raw_trace {
        std::vector<uintptr_t> frames;
        explicit raw_trace(std::vector<uintptr_t>&& frames);
        object_trace resolve_object_trace() const;
        stacktrace resolve() const;
        void clear();
        /* iterators exist for this object */
    };

    /*
     * Object trace with object file information for each frame, any accessible symbol information,
     * and the address in the object file for the frame's program counter.
     */
    struct object_frame {
        std::string obj_path;
        std::string symbol;
        uintptr_t raw_address = 0;
        uintptr_t obj_address = 0;
    };

    struct object_trace {
        std::vector<object_frame> frames;
        explicit object_trace(std::vector<object_frame>&& frames);
        stacktrace resolve() const;
        void clear();
        /* iterators exist for this object */
    };

    /*
     * Resolved stacktrace object.
     */
    struct stacktrace_frame {
        uintptr_t address;
        std::uint_least32_t line;
        std::uint_least32_t col;
        std::string filename;
        std::string symbol;
        bool operator==(const stacktrace_frame& other) const;
        bool operator!=(const stacktrace_frame& other) const;
    };

    struct stacktrace {
        std::vector<stacktrace_frame> frames;
        explicit stacktrace(std::vector<stacktrace_frame>&& frames);
        void print() const;
        void print(std::ostream& stream) const;
        void print(std::ostream& stream, bool color) const;
        std::string to_string() const;
        void clear();
        /* iterators exist for this object */
    };

    /*
     * Trace generation
     */
    raw_trace generate_raw_trace(std::uint32_t skip = 0);
    object_trace generate_object_trace(std::uint32_t skip = 0);
    stacktrace generate_trace(std::uint32_t skip = 0);

    /*
     * Utilities
     */
    std::string demangle(const std::string& name);

    // Traced exception class
    // Extending classes should call the exception constructor with a skip value of 1.
    class exception : public std::exception {
        explicit exception(uint32_t skip)
    public:
        explicit exception();
        const char* what() const noexcept override;
    };

    class exception_with_message : public exception {
        explicit exception_with_message(std::string&& message_arg, uint32_t skip)
    public:
        explicit exception_with_message(std::string&& message_arg);
        const char* what() const noexcept override;
    };

    // All stdexcept errors have analogs here. Same constructor as exception_with_message.
    class logic_error      : exception_with_message { ... };
    class domain_error     : exception_with_message { ... };
    class invalid_argument : exception_with_message { ... };
    class length_error     : exception_with_message { ... };
    class out_of_range     : exception_with_message { ... };
    class runtime_error    : exception_with_message { ... };
    class range_error      : exception_with_message { ... };
    class overflow_error   : exception_with_message { ... };
    class underflow_error  : exception_with_message { ... };
}

• CPPTRACE_STATIC=On/Off: Create cpptrace as a static library.
• CPPTRACE_HARD_MAX_FRAMES=<number>: Some back-ends write to a fixed-size buffer. This is the size of that buffer. Default is 100.

For the most part I'm happy with the state of the library. But I'm sure that there is room for improvement and issues will exist. If you encounter any issue, please let me know! If you find any pain-points in the library, please let me know that too.

A note about performance: For handling of DWARF symbols there is a lot of room to explore for performance optimizations and time-memory tradeoffs. If you find the current implementation is either slow or using too much memory, I'd be happy to explore some of these options.

A couple things I'd like to fix in the future:

• On MacOS .dSYM files are required
• On Windows when collecting symbols with dbghelp (msvc/clang) parameter types are almost perfect but due to limitations in dbghelp the library cannot accurately show const and volatile qualifiers or rvalue references (these appear as pointers).
• On Windows unwinding with CaptureStackBackTrace (msvc/clang) can sometimes produce program counters that are after the call instruction. Execinfo suffers from the same problem, but libgcc's _Unwind provides a means to detect this. I would like to find a solution on windows so stack traces are more accurate.

With CMake FetchContent:

include(FetchContent)
FetchContent_Declare(
  cpptrace
  GIT_REPOSITORY https://github.com/jeremy-rifkin/cpptrace.git
  GIT_TAG        v0.1.1 # <HASH or TAG>
)
FetchContent_MakeAvailable(cpptrace)
target_link_libraries(your_target cpptrace)

It's as easy as that. Cpptrace will automatically configure itself for your system. Note: On windows and macos some extra work is required, see below.

Be sure to configure with -DCMAKE_BUILD_TYPE=Debug or -DDCMAKE_BUILD_TYPE=RelWithDebInfo for symbols and line information.

git clone https://github.com/jeremy-rifkin/cpptrace.git
git checkout v0.1.1
mkdir cpptrace/build
cd cpptrace/build
cmake .. -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=On
make -j
sudo make install

Using through cmake:

find_package(cpptrace REQUIRED)
target_link_libraries(<your target> cpptrace::cpptrace)

Be sure to configure with -DCMAKE_BUILD_TYPE=Debug or -DDCMAKE_BUILD_TYPE=RelWithDebInfo for symbols and line information.

Or compile with -lcpptrace:

g++ main.cpp -o main -g -Wall -lcpptrace
./main

If you get an error along the lines of

error while loading shared libraries: libcpptrace.so: cannot open shared object file: No such file or directory

You may have to run sudo /sbin/ldconfig to create any necessary links and update caches so the system can find libcpptrace.so (I had to do this on Ubuntu). Only when installing system-wide. Usually your package manger does this for you when installing new libraries.

git clone https://github.com/jeremy-rifkin/cpptrace.git
git checkout v0.1.1
mkdir cpptrace/build
cd cpptrace/build
cmake .. -DCMAKE_BUILD_TYPE=Release
msbuild cpptrace.sln
msbuild INSTALL.vcxproj

To install just for the local user (or any custom prefix):

git clone https://github.com/jeremy-rifkin/cpptrace.git
git checkout v0.1.1
mkdir cpptrace/build
cd cpptrace/build
cmake .. -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=On -DCMAKE_INSTALL_PREFIX=$HOME/wherever
make -j
sudo make install

Using through cmake:

find_package(cpptrace REQUIRED PATHS $ENV{HOME}/wherever)
target_link_libraries(<your target> cpptrace::cpptrace)

Using manually:

g++ main.cpp -o main -g -Wall -I$HOME/wherever/include -L$HOME/wherever/lib -lcpptrace

Coming soon

Windows and macos require a little extra work to get everything in the right place

# Copy the cpptrace.dll on windows to the same directory as the executable for your_target.
# Not required if static linking.
if(WIN32)
  add_custom_command(
    TARGET your_target POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E copy_if_different
    $<TARGET_FILE:cpptrace>
    $<TARGET_FILE_DIR:your_target>
  )
endif()

# Create a .dSYM file on macos. Currently required, but hopefully not for long
if(APPLE)
  add_custom_command(
    TARGET your_target
    POST_BUILD
    COMMAND dsymutil $<TARGET_FILE:your_target>
  )
endif()

To static link the library set -DCPPTRACE_STATIC=On.

Cpptrace supports a number of back-ends and middle-ends to produce stack traces. Stack traces are produced in roughly three steps: Unwinding, symbol resolution, and demangling. Cpptrace by default on linux / macos will generate traces with _Unwind_Backtrace, libdwarf, and __cxa_demangle. On windows traces are generated by default with CaptureStackBackTrace and dbghelp.h (no demangling is needed with dbghelp). Under mingw libdwarf and dbghelp.h are used, along with __cxa_demangle. Support for these is the main focus of cpptrace and they should work well. If you want to use a different back-end such as addr2line, however, you can configure the library to do so.

Unwinding

These back-ends require a fixed buffer has to be created to read addresses into while unwinding. By default the buffer can hold addresses for 100 frames (beyond the skip frames). This is configurable with CPPTRACE_HARD_MAX_FRAMES.

Symbol resolution

*: Requires installation

Note for addr2line: By default cmake will resolve an absolute path to addr2line to bake into the library. This path can be configured with CPPTRACE_ADDR2LINE_PATH, or CPPTRACE_ADDR2LINE_SEARCH_SYSTEM_PATH can be used to have the library search the system path for addr2line at runtime. This is not the default to prevent against path injection attacks.

Demangling

Lastly, depending on other back-ends used a demangler back-end may be needed.

More?

There are plenty more libraries that can be used for unwinding, parsing debug information, and demangling. In the future more back-ends can be added. Ideally this library can "just work" on systems, without additional installation work.

Summary of all library configuration options:

Back-ends:

• CPPTRACE_GET_SYMBOLS_WITH_LIBDWARF=On/Off
• CPPTRACE_GET_SYMBOLS_WITH_DBGHELP=On/Off
• CPPTRACE_GET_SYMBOLS_WITH_LIBBACKTRACE=On/Off
• CPPTRACE_GET_SYMBOLS_WITH_ADDR2LINE=On/Off
• CPPTRACE_GET_SYMBOLS_WITH_LIBDL=On/Off
• CPPTRACE_GET_SYMBOLS_WITH_NOTHING=On/Off
• CPPTRACE_UNWIND_WITH_UNWIND=On/Off
• CPPTRACE_UNWIND_WITH_EXECINFO=On/Off
• CPPTRACE_UNWIND_WITH_WINAPI=On/Off
• CPPTRACE_UNWIND_WITH_NOTHING=On/Off
• CPPTRACE_DEMANGLE_WITH_CXXABI=On/Off
• CPPTRACE_DEMANGLE_WITH_NOTHING=On/Off

Back-end configuration:

• CPPTRACE_STATIC=On/Off: Create cpptrace as a static library.
• CPPTRACE_BACKTRACE_PATH=<string>: Path to libbacktrace backtrace.h, needed when compiling with clang/
• CPPTRACE_HARD_MAX_FRAMES=<number>: Some back-ends write to a fixed-size buffer. This is the size of that buffer. Default is 100.
• CPPTRACE_ADDR2LINE_PATH=<string>: Specify the absolute path to the addr2line binary for cpptrace to invoke. By default the config script will search for a binary and use that absolute path (this is to prevent against path injection).
• CPPTRACE_ADDR2LINE_SEARCH_SYSTEM_PATH=On/Off: Specifies whether cpptrace should let the system search the PATH environment variable directories for the binary.

Testing:

• CPPTRACE_BUILD_TEST Build a small test program
• CPPTRACE_BUILD_DEMO Build a small demo program
• CPPTRACE_BUILD_TEST_RDYNAMIC Use -rdynamic when compiling the test program

Cpptrace currently uses integration and functional testing, building and running under every combination of back-end options. The implementation is based on github actions matrices and driven by python scripts located in the ci/ folder. Testing used to be done by github actions matrices directly, however, launching hundreds of two second jobs was extremely inefficient. Test outputs are compared against expected outputs located in test/expected/. Stack trace addresses may point to the address after an instruction depending on the unwinding back-end, and the python script will check for an exact or near-match accordingly.

This library is under the MIT license.

Libdwarf is bundled as part of this library so the code in bundled/libdwarf is LGPL. If this library is statically linked with libdwarf then the library's binary will itself be LGPL.