1// Copyright 2013 The Go Authors. All rights reserved.
 2// Use of this source code is governed by a BSD-style
 3// license that can be found in the LICENSE file.
 4
 5package cgo
 6
 7import (
 8	"errors"
 9	"fmt"
10	"go/build"
11	"os/exec"
12	"strings"
13)
14
15// pkgConfig runs pkg-config with the specified arguments and returns the flags it prints.
16func pkgConfig(mode string, pkgs []string) (flags []string, err error) {
17	cmd := exec.Command("pkg-config", append([]string{mode}, pkgs...)...)
18	out, err := cmd.CombinedOutput()
19	if err != nil {
20		s := fmt.Sprintf("%s failed: %v", strings.Join(cmd.Args, " "), err)
21		if len(out) > 0 {
22			s = fmt.Sprintf("%s: %s", s, out)
23		}
24		return nil, errors.New(s)
25	}
26	if len(out) > 0 {
27		flags = strings.Fields(string(out))
28	}
29	return
30}
31
32// pkgConfigFlags calls pkg-config if needed and returns the cflags
33// needed to build the package.
34func pkgConfigFlags(p *build.Package) (cflags []string, err error) {
35	if len(p.CgoPkgConfig) == 0 {
36		return nil, nil
37	}
38	return pkgConfig("--cflags", p.CgoPkgConfig)
39}