Conversion between common time and strings in Linux

In Linux, it is common to encounter time and string conversions, with two functions specifically corresponding conversions.

1. Time-to-string function strftime

Function prototypes: size_t strftime (char *s,size_t Maxsize,char *format,conststruct TM *timeptr)

The Strftime function formats the time and date represented by the TM structure that the timeptr points to, and the result is placed in the string s. The length of the string is set to a minimum of maxsize characters. Format strings are used to control the characters that are written to the string, which contains the ordinary characters that will be passed to the string, and the conversion controls that arrange the time and date formats.

Input: const struct TM *timeptr

Output: Char *s,size_t Maxsize,char *format

2, string to time function strptime

Function prototypes: Char *strptime (const char *buf,const char*format,struct TM *timeptr)

The format string is constructed exactly like the strftime format string, and Strptime returns a pointer to the character after the last character processed by the conversion process.

Input: const char *buf,const char *format

Output: struct TM *timeptr

Experiment Code:

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

int main ()
{
struct TM Tm_time;
Strptime ("2010-11-15 10:39:30", "%y-%m-%d%h:%m:%s", &tm_time);
printf ("%ld/n", Mktime (&tm_time));
printf ("-------------------------------------/n");

Char szbuf[256] = {0};
time_t timer = time (NULL);
Strftime (szbuf, sizeof (SZBUF), "%y-%m-%d%h:%m:%s", LocalTime (&timer));
printf ("%s/n", szbuf);

return 0;
}

Operation Result:

1289788770

-------------------------------------

2017-07-11 on 19:4

The conversion control is shown in the following table:

Convert a control character	Description
%a	Abbreviated form of the day of the week
%A	Full name of the day of the week
%b	Abbreviated form of the month
%B	Full name of the month
%c	Date and time
%d	Date in the month, 0-31
%H	Hours, 00-23
%I	12 hours of input, 01-12
%j	Date in year, 001-366
%m	Month in year, 01-12
%M	Points, 00-59
%p	Morning or afternoon
%s	Seconds, 00-60
%u	Day of the week, 1-7
%w	Day of the week, 0-6
%x	Date in local format
%x	Time in local format
%y	Last two digits in the year, 00-99
%Y	Years
%Z	Geographic time zone Name

Conversion between common time and strings in Linux