C sleep 方法阻止输出到控制台 [英] C sleep method obstructs output to console

问题描述

我有一个 C 程序，我只是想在其中测试是否可以在安装模块时重现 npm install 中使用的控制台微调器.这个特殊的微调器只是按以下顺序旋转:

I have a C program, where I just wanted to test if I could reproduce a console spinner used in npm install while it installs a module. This particular spinner simply spins in this order:

|<代码>/<代码>-\

在同一个空间，所以我使用以下程序:

on the same space, so I use the following program:

#include <stdio.h>

int main() {
    char sequence[4] = "|/-\\";

    while(1) {
        for(int i = 0; i < 4; i++) {
            // \b is to make the character print to the same space
            printf("\b%c", sequence[i]);
            // now I want to delay here ~0.25s
        }
    }
}

所以我从 <time.h> 找到了一种让它休息那么长时间的方法.文档并制作了这个程序:

So I found a way to make it rest for that long from <time.h> documentation and made this program:

#include <stdio.h>
#include <time.h>

void sleep(double seconds) {
    clock_t then;

    then = clock();

    while(((double)(clock() - then) / CLOCKS_PER_SEC) < seconds); //do nothing
}

int main() {
    char sequence[4] = "|/-\\";

    while(1) {
        for(int i = 0; i < 4; i++) {
            printf("\b%c", sequence[i]);
            sleep(0.25);
        }
    }
}

但是现在没有任何东西打印到控制台.有谁知道我如何才能产生我想要的行为?

But now nothing prints to the console. Does anyone know how I can go about producing the behavior I want?

编辑根据似乎流行的观点，我已将上面的代码更新为以下内容:

EDIT According to what appears to be popular opinion, I've updated my code above to be the following:

#include <stdio.h>
#include <unistd.h>

int main() {
    char sequence[4] = "|/-\\";

    while(1) {
        for(int i = 0; i < 4; i++) {
            printf("\b%c", sequence[i]);
            /* fflush(stdout); */
            // commented out to show same behavior as program above
            usleep(250000); // 250000 microseconds = 0.25 seconds
        }
    }
}

推荐答案

写入控制台后需要刷新.否则，程序将缓冲您的输出:

You will need to flush after you wrote to the console. Otherwise, the program will buffer your output:

fflush(stdout);

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