Let's talk about how to build a local library in Golang

Golang is an open source programming language, which is mainly used for the development of web applications. Compared with other programming languages, Golang has higher efficiency and more convenient syntax. In Golang, we can use native libraries to easily access the underlying resources of the operating system. This article will introduce how to build a local library in Golang to better realize our project needs.

1. Determine project requirements

Before we start building the local library, we need to clarify our project requirements. What we need to consider includes but is not limited to: the type, function, implementation method of the local library, etc. Only by accurately understanding the project requirements can we better build local libraries.

2. Writing C Code

First, we need to write C code. Golang provides a special syntax C that can be easily embedded in C code. Here is some sample code:

#include <stdio.h>
#include <stdlib.h>

void hello() {
    printf("Hello world!\n");
}

int add(int x, int y) {
    return x + y;
}

The above code defines two functions: hello() and add(). Among them, the hello() function outputs the "Hello world!" string, and the add() function is an addition function that returns the sum of the two input parameters.

3. Writing Go code

Next, we need to write Go code and call functions in C code. First, we need to import the C language package into the Go code, and then use the //go directive to introduce the C code. The following is some sample code:

package main

// #cgo CFLAGS: -I.
// #cgo LDFLAGS: -L. -lhello
// #include "hello.h"
import "C"

func main() {
    C.hello()
    sum := C.add(1, 2)
    fmt.Println(sum)
}

In the above code, we use the //go instruction to introduce C code. Each instruction starts with //go and is followed by a piece of raw C code. We also need to specify the CFLAGS and LDFLAGS parameters in the directive, which represent the options used during compilation and linking respectively. Here we specify CFLAGS as the current directory (indicating the location of the header files) and LDFLAGS as the current directory and the name of the library file.

In Go code, we can call C functions directly. Here, we use C.hello() to call the hello() function in the C code, and then use C.add() to call the C code The addition function in . Note that we also need to declare the C language package first in order to import the C function.

4. Compile native library

Finally, we need to compile the C code into a native library. In Linux, we can use the gcc command to compile C code:

gcc -shared -o libhello.so hello.c

The above command will compile hello.c and link it as a shared library file libhello.so. We need to use the -shared option to specify the compilation mode and the -o option to specify the output file name.

5. Test using the local library

After completing the above steps, we can use the local library. In the Go code directory, we can use the following command to test:

go run main.go

The above command will start our Go program and output the result:

Hello world!
3

At this point, we have successfully built the local library and Used successfully in Go programs. Through the above steps, we can better realize our project needs and meet the project requirements.

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