xref: /oneTBB/Bazel.md (revision e6104c95) 
1# Bazel* build support
2
3The main build system of oneTBB is CMake*.
4[Bazel*](https://bazel.build/) support is community-based.
5The Bazel configuration may not include recommended compiler and/or linker flags used in the official CMake configuration.
6
7---
8**NOTE**
9
10Bazel is not recommended for use by oneTBB maintainers. Thus, it is not used internally.
11
12---
13
14
15The Bazel oneTBB build is currently only intended for a subset of oneTBB that suffices restricted use cases.
16Pull requests to improve the Bazel build experience are welcome.
17
18The standard Bazel approach to handling third-party libraries is static linking. It is the best practice within the Bazel ecosystem.
19
20## Using oneTBB as a dependency
21
22This example demonstrates how to use oneTBB as a dependency within a Bazel project.
23
24The following file structure is assumed:
25
26```
27example
28├── .bazelrc
29├── BUILD.bazel
30├── main.cpp
31└── WORKSPACE.bazel
32```
33
34_WORKSPACE.bazel_:
35```python
36load("@platforms//tools/build_defs/repo:git.bzl", "git_repository")
37
38git_repository(
39    name = "oneTBB",
40    branch = "master",
41    remote = "https://github.com/oneapi-src/oneTBB/",
42)
43```
44
45In the *WORKSPACE* file, the oneTBB GitHub* repository is fetched.
46
47_BUILD.bazel_:
48
49```python
50cc_binary(
51    name = "Demo",
52    srcs = ["main.cpp"],
53    deps = ["@oneTBB//:tbb"],
54)
55```
56
57The *BUILD* file defines a binary named `Demo` that has a dependency to oneTBB.
58
59_main.cpp_:
60
61```c++
62#include "oneapi/tbb/version.h"
63
64#include <iostream>
65
66int main() {
67    std::cout << "Hello from oneTBB "
68              << TBB_VERSION_MAJOR << "."
69              << TBB_VERSION_MINOR << "."
70              << TBB_VERSION_PATCH
71              << "!" << std::endl;
72
73    return 0;
74}
75```
76
77The expected output of this program is the current version of oneTBB.
78
79Switch to the folder with the files created earlier and run the binary with `bazel run //:Demo`.
80
81## Build oneTBB using Bazel
82
83Run ```bazel build //...``` in the oneTBB root directory.
84
85## Compiler support
86
87The Bazel build uses the compiler flag `-mwaitpkg` in non-Windows* builds.
88This flag is supported by the GNU* Compiler Collection (GCC) version 9.3, Clang* 12, and newer versions of those tools.
89
90
91---
92**NOTE**
93
94To use the Bazel build with earlier versions of GCC, remove `-mwaitpkg` flag as it leads to errors during compilation.
95
96---
97