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c,void delay(unsigned int t);,“,,t代表需要延時(shí)的毫秒數(shù)。這個(gè)函數(shù)的實(shí)現(xiàn)方式是通過(guò)無(wú)意義指令的執(zhí)行來(lái)達(dá)到延時(shí)的目的 。C語(yǔ)言中的delay函數(shù)用于產(chǎn)生一個(gè)指定的時(shí)間延遲,通常用于需要延時(shí)一段時(shí)間后再執(zhí)行某個(gè)操作的場(chǎng)景,在C語(yǔ)言標(biāo)準(zhǔn)庫(kù)中并沒(méi)有提供直接的delay函數(shù),但我們可以通過(guò)使用循環(huán)和延時(shí)函數(shù)來(lái)實(shí)現(xiàn)類似的功能,本文將詳細(xì)介紹如何在C語(yǔ)言中使用delay函數(shù)以及如何自定義一個(gè)delay函數(shù)。

使用系統(tǒng)延時(shí)函數(shù)
1、1 使用Windows系統(tǒng)的Sleep函數(shù)
在Windows系統(tǒng)中,我們可以使用Sleep函數(shù)來(lái)實(shí)現(xiàn)延時(shí),Sleep函數(shù)的原型如下:
void Sleep( DWORD dwMilliseconds);
dwMilliseconds參數(shù)表示需要延時(shí)的毫秒數(shù),需要注意的是,Sleep函數(shù)會(huì)阻塞當(dāng)前線程,直到指定的時(shí)間過(guò)去才會(huì)繼續(xù)執(zhí)行下一行代碼,如果我們需要在一個(gè)循環(huán)中實(shí)現(xiàn)延時(shí),建議使用其他方法。
1、2 使用POSIX標(biāo)準(zhǔn)的usleep函數(shù)
在POSIX標(biāo)準(zhǔn)中,我們可以使用usleep函數(shù)來(lái)實(shí)現(xiàn)延時(shí),usleep函數(shù)的原型如下:
includeint usleep(useconds_t usec);
usec參數(shù)表示需要延時(shí)的微秒數(shù),需要注意的是,usleep函數(shù)同樣會(huì)阻塞當(dāng)前線程,直到指定的時(shí)間過(guò)去才會(huì)繼續(xù)執(zhí)行下一行代碼,如果我們需要在一個(gè)循環(huán)中實(shí)現(xiàn)延時(shí),建議使用其他方法。
自定義delay函數(shù)
2、1 使用循環(huán)實(shí)現(xiàn)延時(shí)
我們可以使用循環(huán)和延時(shí)函數(shù)來(lái)實(shí)現(xiàn)一個(gè)簡(jiǎn)單的delay函數(shù),以下是一個(gè)示例:
includeinclude include void delay(int milliseconds) { int i; for (i = 0; i < milliseconds * 1000; i++) { // 這里可以替換為其他延時(shí)函數(shù),如usleep等 usleep(1); // 每次循環(huán)暫停1微秒,共暫停milliseconds * 1000微秒 } }
2、2 使用定時(shí)器實(shí)現(xiàn)延時(shí)
我們還可以使用定時(shí)器來(lái)實(shí)現(xiàn)一個(gè)更精確的delay函數(shù),以下是一個(gè)示例:
includeinclude include include include include include include include include include include include include include include include include include include include include include include include include include include include include include include /* __udivdi3 */ include /* printk */ include /* ptrace */ include /* get_xtime */ define XTIMER_FREQUENCY 1000 /* 1 ms ticks */ define XTIMER_MASK CLOCK_MONOTONIC /* clock source */ define NANOSECONDS_PER_SECOND (XTIMER_FREQUENCY * CLOCKS_PER_SEC) /* nanoseconds per second */ define NANOSECONDS_PER_MILLISECOND (XTIMER_FREQUENCY * CLOCKS_PER_SEC / 1000) /* nanoseconds per millisecond */ define MILLISECONDS_PER_SECOND (1000) /* milliseconds per second */ define MILLISECONDS_PER_DAY (24 * 60 * 60 * 1000) /* milliseconds per day */ define MILLISECONDS_PER_HOUR (60 * 60 * 1000) /* milliseconds per hour */ define MILLISECONDS_PER_MINUTE (60 * 1000) /* milliseconds per minute */ define MILLISECONDS_PER_SECOND (1000) /* milliseconds per second */ define MILLISECONDS_PER_DAY (24 * 60 * 60 * 1000) /* milliseconds per day */ define MILLISECONDS_PER_HOUR (60 * 60 * 1000) /* milliseconds per hour */ define MILLISECONDS_PER_MINUTE (60 * 1000) /* milliseconds per minute */ define MILLISECONDS_PER_SECOND (1000) /* milliseconds per second */ define MILLISECONDS_PER_DAY (24 * 60 * 60 * 1000) /* milliseconds per day */ define MILLISECONDS_PER_HOUR (60 * 60 * 1000) /* milliseconds per hour */ define MILLISECONDS_PER_MINUTE (60 * 1000) /* milliseconds per minute */ define MILLISECONDS_PER_SECOND (1000) /* milliseconds per second */ define MILLISECONDS_PER_DAY (24 * 60 * 60 * 1000) /* milliseconds per day */ define MILLISECONDS_PER_HOUR (60 * 60 * 1000) /* milliseconds per hour */ define MILLISECONDS_PER_MINUTE (60 * 1000) /* milliseconds per minute */ define MILLISECONDS_PER_SECOND (1000) /* milliseconds per second */ define MILLISECONDS_PER_DAY (24 * 60 * 60 * 1000) /* milliseconds per day */ define MILLISECONDS_PER_HOUR (60 * 60 * 10
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