description: Fix C++ build errors, CMake issues, and linker problems incrementally. Invokes the cpp-build-resolver agent for minimal, surgical fixes.

C++ Build and Fix

This command invokes the cpp-build-resolver agent to incrementally fix C++ build errors with minimal changes.

What This Command Does

1. Run Diagnostics: Execute cmake --build, clang-tidy, cppcheck
2. Parse Errors: Group by file and sort by severity
3. Fix Incrementally: One error at a time
4. Verify Each Fix: Re-run build after each change
5. Report Summary: Show what was fixed and what remains

When to Use

Use /cpp-build when:

• cmake --build build fails with errors
• Linker errors (undefined references, multiple definitions)
• Template instantiation failures
• Include/dependency issues
• After pulling changes that break the build

Diagnostic Commands Run

# CMake configure
cmake -B build -S .

# Build
cmake --build build 2>&1 | head -100

# Static analysis (if available)
clang-tidy src/*.cpp -- -std=c++17
cppcheck --enable=all src/

Example Session

User: /cpp-build

Agent:
# C++ Build Resolution

## Initial Diagnostics

$ cmake --build build

src/service/user.cpp:25:15: error: use of undeclared identifier 'UserRepository'

src/handler/api.cpp:42:9: error: no matching function for call to 'process'

src/handler/api.cpp:58:1: error: non-void function does not return a value

Errors found: 3

## Fix 1: Undeclared Identifier

File: src/service/user.cpp:25
Error: use of undeclared identifier 'UserRepository'
Cause: Missing include

// Added include

#include "repository/user_repository.hpp"

$ cmake --build build

2 errors remaining

## Fix 2: No Matching Function

File: src/handler/api.cpp:42
Error: no matching function for call to 'process'

// Changed

process(params.get("count"));

// To

process(std::stoi(params.get("count")));

$ cmake --build build

1 error remaining

## Fix 3: Missing Return

File: src/handler/api.cpp:58
Error: non-void function does not return a value

std::optional<User> getUser(const std::string& id) {

if (id.empty()) {

return std::nullopt;

}

auto user = findUser(id);

// Added missing return

return user;

}

$ cmake --build build

Build successful!

## Final Verification

$ ctest --test-dir build --output-on-failure

Test project build

1/5 Test #1: unit_tests ........ Passed 0.02 sec

2/5 Test #2: integration_tests Passed 0.15 sec

All tests passed.

## Summary

| Metric | Count |
|--------|-------|
| Build errors fixed | 3 |
| Linker errors fixed | 0 |
| Files modified | 2 |
| Remaining issues | 0 |

Build Status: PASS: SUCCESS

Common Errors Fixed

Fix Strategy

1. Compilation errors first - Code must compile
2. Linker errors second - Resolve undefined references
3. Warnings third - Fix with -Wall -Wextra
4. One fix at a time - Verify each change
5. Minimal changes - Don't refactor, just fix

Stop Conditions

The agent will stop and report if:

• Same error persists after 3 attempts
• Fix introduces more errors
• Requires architectural changes
• Missing external dependencies

Related Commands

• /cpp-test - Run tests after build succeeds
• /cpp-review - Review code quality
• verification-loop skill - Full verification loop

Related

• Agent: agents/cpp-build-resolver.md
• Skill: skills/cpp-coding-standards/