std::time_get::get
Defined in header <locale> | | |
|---|---|---|
public: iter_type get(iter_type beg, iter_type end, std::ios_base& str, std::ios_base::iostate& err, std::tm* t, const char_type* fmtbeg, const char_type* fmtend) const; | (1) | (since C++11) |
protected: virtual iter_type do_get(iter_type neg, iter_type end, std::ios_base& str, std::ios_base::iostate& err, std::tm *t, char format, char modifier) const; | (2) | (since C++11) |
1%29分析输入字符序列中的日期和时间。[beg, end)根据字符序列中提供的格式[fmtbeg, fmtend)预计该格式将遵循下面描述的格式，尽管可以通过重写来定制每个格式说明符的实际处理。do_get...get函数执行以下操作：首先，清除err通过执行err =std::ios_base::goodbit然后进入一个循环，当下列条件变为真时，该循环将终止%28，按此顺序检查为%29：
%29所有字符都已从格式字符串%28中读取fmtbeg == fmtend%29
B%29解析错误%28err !=std::ios_base::goodbit%29
C%29所有字符都已从输入序列%28中读取beg == end如果此条件终止循环，则该函数将同时设置eofbit和failbit在err
在循环的主体中，执行以下步骤：
如果格式字符串中的下一个字符是'%'，后面跟着一个或两个构成有效字符的字符。std::get_time转换说明符%28参见%29下面，这些字符用于调用do_get(beg, end, str, err, t, format, modifier)，在哪里format主要转换说明符字符，以及modifier是可选修饰符%28，它出现在%和格式字符，如果存在%29。如果没有修饰符，则值'\0'被使用了。如果格式字符串模棱两可或过早结束，则无法在之后确定转换说明符。'%'，，，eofbit设为err循环被终止。如果，在打电话到do_get中没有设置错误位。err，函数递增fmtbeg在转换说明符之后直接指向并继续循环。
B%29如果下一个字符是空格，由流中提供的区域设置指示str%28i.e.std::isspace(*fmtbeg, str.getloc()) == true，该函数不断递增。fmtbeg直到它变成等于fmtend或指向非空白字符。
c%29如果根据大小写不敏感的比较，格式字符串中的下一个字符与输入流中的下一个字符等效，则函数将两个序列推进一个字符。++fmtbeg, ++beg;并继续循环，否则，它将设置failbit在err...
2%29解析输入序列中的一个转换说明符。[beg, end)并更新std::tm结构指向t因此。
首先，清除err通过执行err =std::ios_base::goodbit然后从输入序列中读取字符。[beg, end)预期的std::time_get格式说明符'%'，，，modifier%28如果没有'\0'%29，和format如果这些字符未组合成有效的转换说明符，则设置failbit在err如果读取字符后到达输入流的末尾，则设置eofbit在err如果成功地解析了输入字符串，则更新*t对于复杂的转换说明符，如'%x'或'%c'，或者使用修饰符的指令。'E'和'O'，函数可能无法确定要存储在其中的一些值。*t在这种情况下，eofbit在err并使这些字段处于未指定的状态。
参数
beg | - | iterator designating the start of the sequence to parse | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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end | - | one past the end iterator for the sequence to parse | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
str | - | a stream object that this function uses to obtain locale facets when needed, e.g. std::ctype to skip whitespace or std::collate to compare strings | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
err | - | stream error flags object that is modified by this function to indicate errors | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
t | - | pointer to the std::tm object that will hold the result of this function call | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
fmtbeg | - | pointer to the first character of a sequence of char_type characters specifying the conversion format The format string consists of zero or more conversion specifiers, whitespace characters, and ordinary characters (except %). Each ordinary character is expected to match one character in the input stream in case-insensitive comparison. Each whitespace character matches arbitrary whitespace in the input string. Each conversion specification begins with % character, optionally followed by E or O modifier (ignored if unsupported by the locale), followed by the character that determines the behavior of the specifier. The format specifiers match the POSIX function strptime(): Conversion specifier Explanation Writes to fields % matches a literal %. The full conversion specification must be %%. (none) t matches any whitespace. (none) n matches any whitespace. (none) Year Y parses full year as a 4 digit decimal number, leading zeroes permitted but not required tm_year EY parses year in the alternative representation, e.g.平成23年 (year Heisei 23) which writes 2011 to tm_year in ja_JP locale tm_year y parses last 2 digits of year as a decimal number. Range 69,99 results in values 1969 to 1999, range 00,68 results in 2000-2068 tm_year Oy parses last 2 digits of year using the alternative numeric system, e.g. 十一 is parsed as 11 in ja_JP locale tm_year Ey parses year as offset from locale's alternative calendar period %EC tm_year C parses the first 2 digits of year as a decimal number (range 00,99) tm_year EC parses the name of the base year (period) in the locale's alternative representation, e.g. 平成 (Heisei era) in ja_JP tm_year Month b parses the month name, either full or abbreviated, e.g. Oct tm_mon h synonym of b tm_mon B synonym of b tm_mon m parses the month as a decimal number (range 01,12), leading zeroes permitted but not required tm_mon Om parses the month using the alternative numeric system, e.g. 十二 parses as 12 in ja_JP locale tm_mon Week U parses the week of the year as a decimal number (Sunday is the first day of the week) (range 00,53), leading zeroes permitted but not required tm_year, tm_wday, tm_yday OU parses the week of the year, as by %U, using the alternative numeric system, e.g. 五十二 parses as 52 in ja_JP locale tm_year, tm_wday, tm_yday W parses the week of the year as a decimal number (Monday is the first day of the week) (range 00,53), leading zeroes permitted but not required tm_year, tm_wday, tm_yday OW parses the week of the year, as by %W, using the alternative numeric system, e.g. 五十二 parses as 52 in ja_JP locale tm_year, tm_wday, tm_yday Day of the year/month j parses day of the year as a decimal number (range 001,366), leading zeroes permitted but not required tm_yday d parses the day of the month as a decimal number (range 01,31), leading zeroes permitted but not required tm_mday Od parses the day of the month using the alternative numeric system, e.g 二十七 parses as 27 in ja_JP locale, leading zeroes permitted but not required tm_mday e synonym of d tm_mday Oe synonym of Od tm_mday Day of the week a parses the name of the day of the week, either full or abbreviated, e.g. Fri tm_wday A synonym of a tm_wday w parses weekday as a decimal number, where Sunday is 0 (range 0-6) tm_wday Ow parses weekday as a decimal number, where Sunday is 0, using the alternative numeric system, e.g. 二 parses as 2 in ja_JP locale tm_wday Hour, minute, second H parses the hour as a decimal number, 24 hour clock (range 00-23), leading zeroes permitted but not required tm_hour OH parses hour from 24-hour clock using the alternative numeric system, e.g. 十八 parses as 18 in ja_JP locale tm_hour I parses hour as a decimal number, 12 hour clock (range 01,12), leading zeroes permitted but not required tm_hour OI parses hour from 12-hour clock using the alternative numeric system, e.g. 六 reads as 06 in ja_JP locale tm_hour M parses minute as a decimal number (range 00,59), leading zeroes permitted but not required tm_min OM parses minute using the alternative numeric system, e.g. 二十五 parses as 25 in ja_JP locale tm_min S parses second as a decimal number (range 00,60), leading zeroes permitted but not required tm_sec OS parses second using the alternative numeric system, e.g. 二十四 parses as 24 in ja_JP locale tm_sec Other c parses the locale's standard date and time string format, e.g. Sun Oct 17 04:41:13 2010 (locale dependent) all Ec parses the locale's alternative date and time string format, e.g. expecting 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale all x parses the locale's standard date representation all Ex parses the locale's alternative date representation, e.g. expecting 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale all X parses the locale's standard time representation all EX parses the locale's alternative time representation all D equivalent to "%m / %d / %y " tm_mon, tm_mday, tm_year r parses locale's standard 12-hour clock time (in POSIX, "%I : %M : %S %p") tm_hour, tm_min, tm_sec R equivalent to "%H : %M" tm_hour, tm_min T equivalent to "%H : %M : %S" tm_hour, tm_min, tm_sec p parses the locale's equivalent of a.m. or p.m. tm_hour Note: tm_isdst is not written to, and needs to be set explicitly for use with functions such as mktime. | Conversion specifier | Explanation | Writes to fields | % | matches a literal %. The full conversion specification must be %%. | (none) | t | matches any whitespace. | (none) | n | matches any whitespace. | (none) | Year | Y | parses full year as a 4 digit decimal number, leading zeroes permitted but not required | tm_year | EY | parses year in the alternative representation, e.g.平成23年 (year Heisei 23) which writes 2011 to tm_year in ja_JP locale | tm_year | y | parses last 2 digits of year as a decimal number. Range 69,99 results in values 1969 to 1999, range 00,68 results in 2000-2068 | tm_year | Oy | parses last 2 digits of year using the alternative numeric system, e.g. 十一 is parsed as 11 in ja_JP locale | tm_year | Ey | parses year as offset from locale's alternative calendar period %EC | tm_year | C | parses the first 2 digits of year as a decimal number (range 00,99) | tm_year | EC | parses the name of the base year (period) in the locale's alternative representation, e.g. 平成 (Heisei era) in ja_JP | tm_year | Month | b | parses the month name, either full or abbreviated, e.g. Oct | tm_mon | h | synonym of b | tm_mon | B | synonym of b | tm_mon | m | parses the month as a decimal number (range 01,12), leading zeroes permitted but not required | tm_mon | Om | parses the month using the alternative numeric system, e.g. 十二 parses as 12 in ja_JP locale | tm_mon | Week | U | parses the week of the year as a decimal number (Sunday is the first day of the week) (range 00,53), leading zeroes permitted but not required | tm_year, tm_wday, tm_yday | OU | parses the week of the year, as by %U, using the alternative numeric system, e.g. 五十二 parses as 52 in ja_JP locale | tm_year, tm_wday, tm_yday | W | parses the week of the year as a decimal number (Monday is the first day of the week) (range 00,53), leading zeroes permitted but not required | tm_year, tm_wday, tm_yday | OW | parses the week of the year, as by %W, using the alternative numeric system, e.g. 五十二 parses as 52 in ja_JP locale | tm_year, tm_wday, tm_yday | Day of the year/month | j | parses day of the year as a decimal number (range 001,366), leading zeroes permitted but not required | tm_yday | d | parses the day of the month as a decimal number (range 01,31), leading zeroes permitted but not required | tm_mday | Od | parses the day of the month using the alternative numeric system, e.g 二十七 parses as 27 in ja_JP locale, leading zeroes permitted but not required | tm_mday | e | synonym of d | tm_mday | Oe | synonym of Od | tm_mday | Day of the week | a | parses the name of the day of the week, either full or abbreviated, e.g. Fri | tm_wday | A | synonym of a | tm_wday | w | parses weekday as a decimal number, where Sunday is 0 (range 0-6) | tm_wday | Ow | parses weekday as a decimal number, where Sunday is 0, using the alternative numeric system, e.g. 二 parses as 2 in ja_JP locale | tm_wday | Hour, minute, second | H | parses the hour as a decimal number, 24 hour clock (range 00-23), leading zeroes permitted but not required | tm_hour | OH | parses hour from 24-hour clock using the alternative numeric system, e.g. 十八 parses as 18 in ja_JP locale | tm_hour | I | parses hour as a decimal number, 12 hour clock (range 01,12), leading zeroes permitted but not required | tm_hour | OI | parses hour from 12-hour clock using the alternative numeric system, e.g. 六 reads as 06 in ja_JP locale | tm_hour | M | parses minute as a decimal number (range 00,59), leading zeroes permitted but not required | tm_min | OM | parses minute using the alternative numeric system, e.g. 二十五 parses as 25 in ja_JP locale | tm_min | S | parses second as a decimal number (range 00,60), leading zeroes permitted but not required | tm_sec | OS | parses second using the alternative numeric system, e.g. 二十四 parses as 24 in ja_JP locale | tm_sec | Other | c | parses the locale's standard date and time string format, e.g. Sun Oct 17 04:41:13 2010 (locale dependent) | all | Ec | parses the locale's alternative date and time string format, e.g. expecting 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | all | x | parses the locale's standard date representation | all | Ex | parses the locale's alternative date representation, e.g. expecting 平成23年 (year Heisei 23) instead of 2011年 (year 2011) in ja_JP locale | all | X | parses the locale's standard time representation | all | EX | parses the locale's alternative time representation | all | D | equivalent to "%m / %d / %y " | tm_mon, tm_mday, tm_year | r | parses locale's standard 12-hour clock time (in POSIX, "%I : %M : %S %p") | tm_hour, tm_min, tm_sec | R | equivalent to "%H : %M" | tm_hour, tm_min | T | equivalent to "%H : %M : %S" | tm_hour, tm_min, tm_sec | p | parses the locale's equivalent of a.m. or p.m. | tm_hour |
Conversion specifier | Explanation | Writes to fields | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
% | matches a literal %. The full conversion specification must be %%. | (none) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
t | matches any whitespace. | (none) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
n | matches any whitespace. | (none) |
年
y将全年解析为4位十进制数，允许使用前导零，但不需要tm。[医]年
EY在可选表示中解析年份，例如平成23年%28 Heisei 23%29，其中写入2011到tm。[医]在日本的年份[医]JP地区tm[医]年
y将年的最后2位数字解析为十进制数。范围69，99结果值为1969至1999，范围00682000业绩-2068 tm[医]年
Oy使用替代数字系统分析一年中的最后2位数字，例如，在ja中，十一被解析为11。[医]JP地区tm[医]年
安永将年份与地区%27s替代日历期%ectm相抵。[医]年
C将年的前2位数字解析为十进制数%28范围。0099%29 tm[医]年
EC在地区%27 s替代表示中解析基准年%28周期%29的名称，例如平成%28 Heisei era%29在ja中。[医]JP tm[医]年
月
B解析月份名称，无论是完整的还是缩写的，例如oct tm。[医]蒙
h同义词b tm[医]蒙
b的同义词b tm[医]蒙
M将月份解析为十进制数%28范围01，12%29，前导零允许但不需要tm[医]蒙
OM使用替代的数字系统解析月份，例如在ja中将十二解析为12。[医]JP地区tm[医]蒙
周
将一年中的一周解析为十进制数%28星期日是一周的第一天%29%28范围0053%29，前导零允许但不需要tm[医]年份，tm[医]WDAY，tm[医]日
以%U的方式分析一年中的每周，使用替代的数字系统，例如，在ja中五十二解析为52[医]JP地区tm[医]年份，tm[医]WDAY，tm[医]日
将一年中的一周解析为十进制数%28星期一是一周的第一天%29%28范围。0053%29，前导零允许但不需要tm[医]年份，tm[医]WDAY，tm[医]日
现在使用替代数字系统解析一年中的每周，如%W，例如，在ja中五十二解析为52[医]JP地区tm[医]年份，tm[医]WDAY，tm[医]日
年度/月份的日期
J将一年中的一天解析为十进制数%28范围001366%29，前导零允许但不需要tm[医]日
D将月份中的一天解析为十进制数%28范围。01，31%29，前导零允许但不需要tm[医]马日
OD使用可选的数字系统解析一个月中的一天，例如，在ja中，二十七解析为27。[医]jp地区，前导零允许但不需要tm[医]马日
d tm的同义词[医]马日
OE同义词Od tm[医]马日
一周中的一天
A解析一周中的一天的名称，或者是完整的，或者是缩写的，例如Fri tm。[医]WDAY
tm的同义词[医]WDAY
W将工作日解析为十进制数，其中星期日为0%28范围。0-6%29 tm[医]WDAY
现在将工作日解析为十进制数，其中星期日为0，使用可选的数字系统，例如，在ja中，二解析为2。[医]JP地区tm[医]WDAY
小时，分钟，秒
h将小时解析为十进制数，24小时时钟%28范围00-23%29，前导零允许但不需要tm[医]小时
哦，使用替代的数字系统从24小时的时钟分析小时，例如在ja中十八解析为18。[医]JP地区tm[医]小时
我将小时分析为十进制数，12小时时钟%28范围01，12%29，前导零允许但不需要tm[医]小时
Oi使用可选的数字系统从12小时时钟分析小时，例如，在ja中，六读取为06。[医]JP地区tm[医]小时
M将分钟解析为十进制数%28范围0059%29，前导零允许但不需要tm[医]敏
OM使用替代的数字系统解析分钟，例如在ja中使用二十五解析为25[医]JP地区tm[医]敏
s将秒解析为十进制数%28范围0060%29，前导零允许但不需要tm[医]证交会
操作系统使用替代数字系统进行第二次分析，例如在ja中二十四解析为24[医]JP地区tm[医]证交会
其他
EC分析地区%27s的替代日期和时间字符串格式，例如期望平成23年%28a Heisei 23%29而不是在ja中的2011年%28 28 2011%29。[医]JP地区所有
X解析区域设置%27s标准日期表示所有
例如，期望平成23年%28a Heisei 23%29而不是2011年%28a 2011%29在ja[医]JP地区所有
X解析地区%27s标准时间表示全部
ex解析区域设置%27的可选时间表示ALL
d等于“%m/%d/%y”tm[医]星期一，tm[医]mday，tm[医]年
r解析POSIX中标准的12小时时钟时间%28，“%i：%M：%S%p”%29 tm[医]小时，小时[医]min，tm[医]证交会
r等于“%H：%M”tm[医]小时，小时[医]敏
t等于“%H：%M：%S”tm[医]小时，小时[医]min，tm[医]证交会
P解析相当于上午或下午tm的地区%27s。[医]小时
指示字符序列的最后一个字符的指针。[医]指定转换格式的字符类型
格式-命名转换说明符的字符。
修饰符-在%和转换说明符之间可能出现的可选修饰符
返回值
中的最后一个字符[beg, end)分析得很成功。
注记
不区分大小写的非空白非-'%'格式字符串中的字符，则std::collate提供的区域设置的方面。str通常(但不一定)使用。
如果遇到解析错误，则此函数的许多实现将离开。*t完全不动。
如果这些函数在*t可移植程序应该在调用之前将每个字段初始化为零。get()...
例
二次
#include <iostream>
#include <sstream>
#include <locale>
#include <iomanip>
int main()
{
std::istringstream ss("2011-Februar-18 23:12:34");
ss.imbue(std::locale("de_DE.utf8"));
auto& f = std::use_facet<std::time_get<char>>(std::locale("de_DE.utf8"));
std::tm t{};
std::string s = "%Y-%b-%d %H:%M:%S";
std::ios_base::iostate err = std::ios_base::goodbit;
std::istreambuf_iterator<char> ret = f.get(std::istreambuf_iterator<char>(ss),
std::istreambuf_iterator<char>(),
ss, err, &t, &s[0], &s[0] + s.size());
ss.setstate(err);
if(ss) {
std::cout << "Successfully parsed as " << std::put_time(&t, "%c");
if(ret != std::istreambuf_iterator<char>()) {
std::cout << " Remaining content: ";
std::copy(ret, std::istreambuf_iterator<char>(),
std::ostreambuf_iterator<char>(std::cout));
} else {
std::cout << " The input was fully consumed";
}
} else {
std::cout << "Parse failed. Unparsed string: ";
std::copy(ret, std::istreambuf_iterator<char>(),
std::ostreambuf_iterator<char>(std::cout));
}
std::cout << '\n';
}二次
产出：
二次
Successfully parsed, as Sun Feb 18 23:12:34 2011 The input was fully consumed二次
另见
get_time (C++11) | parses a date/time value of specified format (function template) |
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