Linux Sleep command parameters and usage--linux hibernate delay execution Command __linux

Source: Internet
Author: User
Tags function prototype linux sleep sleep function usleep
Use Rights: All users
Use mode: Sleep [--help] [--version] NUMBER[SMHD]
Description: Sleep can be used to delay the current action for a period of time
Parameter description:
--HELP: Display auxiliary messages
--version: Display version number
Number: Length of time, followed by S, M, H or D
Where S is the second, M is minutes, H is the hour, D is the number of days
Example:
Delay 1 minutes after displaying the current time, and then display the time again:
Date;sleep 1m;date


This command is more used in shell scripting and in programs.


As in the following procedure:

Application:
#include <syswait.h>
Usleep (n)//n microsecond
Sleep (n)//n ms
Sleep (n)//n seconds
Driver:
#include <linux/delay.h>
Mdelay (n)//milliseconds its implementation
#ifdef NOTDEF
#define MDELAY (n) (\
{unsigned long msec= (n); while (msec--) udelay (1000);})
#else
#define MDELAY (n) (\
(__builtin_constant_p (n) && (n) <=max_udelay_ms)? Udelay ((n) *1000): \
({unsigned long msec= (n); while (msec--) udelay (1000);}))
#endif
Call Asm/delay.h's udelay,udelay should be nanosecond delay


Dos:
Sleep (1); Stay for 1 seconds.
Delay (100); Stay for 100 milliseconds
Windows:
Sleep (100); Stay for 100 milliseconds
Linux:
Sleep (1); Stay for 1 seconds.
Usleep (1000); Stay for 1 milliseconds
Each platform is not the same, it is best to define a Cross-platform macro control


Seconds or microseconds. About the delay function sleep ()
Because to write a piece of code, you need to use the sleep () function, in my memory (10) seems to be dormant 10 microseconds, the result is dormant for 10 seconds (under Linux). I think it's strange, because the chief remembers it as if it was a microsecond unit. So I looked it up.

The original Sleep function prototype under Linux is:
unsigned int sleep (unsigned int seconds);
And the Sleep function prototype in MFC is:
void Sleep (DWORD dwmilliseconds);
That is, under Linux (the GCC library used), The sleep () function is in seconds, sleeping (1), or dormant for 1 seconds. The sleep () function under MFC is in microseconds (1000) and sleeps for 1 seconds. Oh, yes. And if you sleep in subtle units under Linux, you can use the thread-hibernate function: void Usleep (unsigned long usec); Don't forget to use #include <system.h> oh.

Also worth mentioning is that Linux has a delay () function, the prototype is extern void delay (unsigned int msec), it can delay msec*4 milliseconds, that is, if you want to delay a second, you can use delay (250);
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