---
sidebar_label: FAQ
---
# FAQ
## Registry not found
```
error: registry not found
```
**Solution:** Make sure `~/.dcr/config.toml` exists:
```toml
[[registry]]
name = "default"
url = "https://index.dcr.pm"
```
And check `DCR_INDEX_PATH`:
```bash
echo $DCR_INDEX_PATH
```
## Compiler not found
```
error: compiler not found
```
**Solution:** Ensure a compiler is installed and available in PATH.
```bash
which gcc
which clang
```
Or specify explicitly via `[toolchain]` in `dcr.toml`.
## openssl-sys build failed
When building DCR from source:
```
error: failed to run custom build command for openssl-sys
```
**Solution:** Install OpenSSL development headers:
```bash
# Ubuntu/Debian
sudo apt install libssl-dev
# Fedora
sudo dnf install openssl-devel
# macOS
brew install openssl
```
## Ctrl+C during build
DCR handles SIGINT: interrupts the current compilation and exits with non-zero code.
## How to create a library?
See [Library Recipe](/docs/recipes/library-project).
## How to cross-compile to Windows?
See [Cross-Compile Recipe](/docs/recipes/cross-to-windows).
## How to create a multi-package project?
See [Workspace Recipe](/docs/recipes/multi-package-workspace).
## Lock file
`dcr.lock` is created during builds (`dcr build`) when registry dependencies are present. To force an update — delete `dcr.lock` and run `dcr build`.