How Can I Successfully Use Conditional Compilation with '// build' in Go?

Conditional Compilation in Golang

You mentioned encountering an issue with conditional compilation in Go. Here's a detailed explanation of the "// build" constraint and "-tags" flag, along with a resolution to your problem.

The "// build" constraint tells the compiler which build tags to use when compiling the file. In your example, you have used "// build main1" for main1.go and "// build main2" for main2.go. This means that these files will only be compiled when the corresponding build tag is specified.

To compile your code with the desired build tag, you can use the "-tags" flag. For example, to compile main1.go only, you can run:

$ go build -tags main1

However, the error you're encountering suggests that you may have encountered a small detail that is crucial for conditional compilation in Go: you must follow the "// build XXX" line with a blank line. This is not explicitly documented, but it is evident in the source code.

Here's a modified version of your code with the blank line added:

main1.go

// +build main1

package main

import (
    "fmt"
)

func main() {
    fmt.Println("This is main 1")
}

main2.go

// +build main2

package main

import (
    "fmt"
)

func main() {
    fmt.Println("This is main 2")
}

Now, running "go build -tags main1" will compile only main1.go, as expected. By following this rule, you can effectively use conditional compilation in Golang to selectively include or exclude files based on the specified build tags.

The above is the detailed content of How Can I Successfully Use Conditional Compilation with '// build' in Go?. For more information, please follow other related articles on the PHP Chinese website!