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1# Bazel support
2
3To get [Bazel](https://bazel.build/) working with {fmt} you can copy the files `BUILD.bazel`, `WORKSPACE.bazel`, and `.bazelversion` from this folder (`support/bazel`) to the root folder of this project. This way {fmt} gets bazelized and can be used with Bazel (e.g. doing a `bazel build //...` on {fmt}).
4
5## Using {fmt} as a dependency
6
7The following minimal example shows how to use {fmt} as a dependency within a Bazel project.
8
9The following file structure is assumed:
10
11```
12example
13├── BUILD.bazel
14├── main.cpp
15└── WORKSPACE.bazel
16```
17
18*main.cpp*:
19
20```c++
21#include "fmt/core.h"
22
23int main() {
24  fmt::print("The answer is {}\n", 42);
25}
26```
27
28The expected output of this example is `The answer is 42`.
29
30*WORKSPACE.bazel*:
31
32```python
33load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
34
35git_repository(
36    name = "fmt",
37    branch = "master",
38    remote = "https://github.com/fmtlib/fmt",
39    patch_cmds = [
40        "mv support/bazel/.bazelversion .bazelversion",
41        "mv support/bazel/BUILD.bazel BUILD.bazel",
42        "mv support/bazel/WORKSPACE.bazel WORKSPACE.bazel",
43    ],
44    # Windows-related patch commands are only needed in the case MSYS2 is not installed.
45    # More details about the installation process of MSYS2 on Windows systems can be found here:
46    # https://docs.bazel.build/versions/main/install-windows.html#installing-compilers-and-language-runtimes
47    # Even if MSYS2 is installed the Windows related patch commands can still be used.
48    patch_cmds_win = [
49        "Move-Item -Path support/bazel/.bazelversion -Destination .bazelversion",
50        "Move-Item -Path support/bazel/BUILD.bazel -Destination BUILD.bazel",
51        "Move-Item -Path support/bazel/WORKSPACE.bazel -Destination WORKSPACE.bazel",
52    ],
53)
54```
55
56In the *WORKSPACE* file, the {fmt} GitHub repository is fetched. Using the attribute `patch_cmds` the  files `BUILD.bazel`, `WORKSPACE.bazel`, and `.bazelversion` are moved to the root of the {fmt} repository. This way the {fmt} repository is recognized as a bazelized workspace.
57
58*BUILD.bazel*:
59
60```python
61cc_binary(
62    name = "Demo",
63    srcs = ["main.cpp"],
64    deps = ["@fmt"],
65)
66```
67
68The *BUILD* file defines a binary named `Demo` that has a dependency to {fmt}.
69
70To execute the binary you can run `bazel run //:Demo`.
71
72# Using Bzlmod
73
74The [Bazel Central Registry](https://github.com/bazelbuild/bazel-central-registry/tree/main/modules/fmt) also provides support for {fmt}.
75