Tuesday coding tips are super short posts about various tidbits mainly from C++, but also from other programming languages I use. You can also follow the #TuesdayCodingTips hashtag on Mastodon and Linkedin.
C++23 brings a new feature that I always wanted since I’ve seen it in C# — stack trace.
When combined with exceptions, it can immensely help with the analysis of user error reports, when you cannot simply attach a debugger. The code snippet shows how to create an exception class that can automatically capture stack trace at the point where it was constructed.
#include <iostream>
#include <stacktrace>
#include <stdexcept>
class stacktrace_error : public std::runtime_error
{
public:
stacktrace_error(std::stacktrace trace = std::stacktrace::current())
: std::runtime_error(std::to_string(trace))
{}
};
void bar() { throw stacktrace_error(); }
void foo() { bar(); }
int main()
{
try
{
foo();
}
catch (std::exception& e)
{
std::cerr << e.what() << std::endl;
/* OUTPUTS:
0> C:\...\Main.cpp(19): Sandbox!bar+0x44
1> C:\...\Main.cpp(25): Sandbox!foo+0x20
2> C:\...\Main.cpp(31): Sandbox!main+0x32
3> D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl(79): Sandbox!invoke_main+0x39
4> D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl(288): Sandbox!__scrt_common_main_seh+0x12E
5> D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl(331): Sandbox!__scrt_common_main+0xE
6> D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_main.cpp(17): Sandbox!mainCRTStartup+0xE
7> KERNEL32!BaseThreadInitThunk+0x14
8> ntdll!RtlUserThreadStart+0x21
*/
}
}
The API even allows you to iterate over each stack entry, but honestly — who needs that?
Note: Linux versions of GCC and Clang have this stupid idea of requiring you to manually link stacktrace (akin to math library), because -std=c++23 is apparently not enough of a feature flag. So don't forget to use -lstdc++_libbacktrace argument for compilation.