Bazel用fmtlib构建项目.Cpp

Question

我正试图在cpp上用位于/usr/lib64/libfmt.so中的动态库构建一个项目。lib模块构建时没有出现错误，但由于某些原因，main失败并出现错误：

INFO: Analyzed target //main:main (1 packages loaded, 7 targets configured).
INFO: Found 1 target...
ERROR: /home/nim/Prg/Cpp/bazel_learn/examples/cpp-tutorial/my_stage/main/BUILD:1:11: SolibSymlink _solib_k8/_U_S_Smain_Cfmt___Umain/libfmt.so failed: missing input file '//main:libfmt.so'
Target //main:main failed to build
Use --verbose_failures to see the command lines of failed build steps.
ERROR: /home/nim/Prg/Cpp/bazel_learn/examples/cpp-tutorial/my_stage/main/BUILD:1:11 SolibSymlink _solib_k8/_U_S_Smain_Cfmt___Umain/libfmt.so failed: 1 input file(s) do not exist
INFO: Elapsed time: 0.248s, Critical Path: 0.04s
INFO: 3 processes: 3 internal.
FAILED: Build did NOT complete successfully

如何正确收集项目？这是BUILD文件。

cc_import (
  name = "fmt",
  # hdrs = ["include/fmt/core.h"],
  shared_library = "libfmt.so",
  visibility = ["//visibility:public"],
)
cc_library (
  name = "lib",
  hdrs = ["lib.hpp"],
  srcs = ["lib.cc"],
  deps = [":fmt"],
  visibility = ["//visibility:public"],
  linkstatic = 0,
)
cc_binary (
  name = "main",
  srcs = ["main.cc"],
  deps = [":lib"],
  linkopts = ["-lfmt"],
  linkstatic = 0,
)

项目结构

├── main
│   ├── BUILD
│   ├── lib.cc
│   ├── lib.hpp
│   └── main.cc
└── WORKSPACE

代码文件：

main.cc

#include "lib.hpp"
int main(int argc, char *argv[]) {
  if ( argc > 1) {
    lib::hello(argv[1]);
  }
  else {
    lib::hello();
  }
  return EXIT_SUCCESS;
}

lib.cc

#include "lib.hpp"
#include <fmt/core.h>
namespace lib {
  void hello(std::string const& name) {
    fmt::print("Hello, {}", name);
  }
}

lib.hpp

#pragma once
#include <string>
namespace lib {
  void hello(std::string const& name = "World");
}

Answer 1

{fmt}附带Bazel支持-您可以这样使用它：

WORKSPACE.bazel

load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
git_repository(
    name = "fmt",
    branch = "master",
    patch_cmds = [
        "mv support/bazel/.bazelrc .bazelrc",
        "mv support/bazel/.bazelversion .bazelversion",
        "mv support/bazel/BUILD.bazel BUILD.bazel",
        "mv support/bazel/WORKSPACE.bazel WORKSPACE.bazel",
    ],
    # Windows related patch commands are only needed in the case MSYS2 is not installed
    patch_cmds_win = [
        "Move-Item -Path support/bazel/.bazelrc -Destination .bazelrc",
        "Move-Item -Path support/bazel/.bazelversion -Destination .bazelversion",
        "Move-Item -Path support/bazel/BUILD.bazel -Destination BUILD.bazel",
        "Move-Item -Path support/bazel/WORKSPACE.bazel -Destination WORKSPACE.bazel",
    ],
    remote = "https://github.com/fmtlib/fmt",
)

BUILD.bazel

cc_binary(
    name = "Demo",
    srcs = ["main.cpp"],
    deps = ["@fmt"],
)

main.cpp

#include "fmt/core.h"
int main() {
  fmt::print("The answer is {}.n", 42);
}

另请参见此处。