From 82ba818ff456bcd6d56a06226e3f27e98fbb55c3 Mon Sep 17 00:00:00 2001 From: Craig Jennings Date: Thu, 14 Aug 2025 22:58:58 -0500 Subject: removing all downloaded devdocs files --- devdocs/c/chrono%2Fmktime.html | 46 ------------------------------------------ 1 file changed, 46 deletions(-) delete mode 100644 devdocs/c/chrono%2Fmktime.html (limited to 'devdocs/c/chrono%2Fmktime.html') diff --git a/devdocs/c/chrono%2Fmktime.html b/devdocs/c/chrono%2Fmktime.html deleted file mode 100644 index d4a34bc9..00000000 --- a/devdocs/c/chrono%2Fmktime.html +++ /dev/null @@ -1,46 +0,0 @@ -

mktime

Defined in header <time.h> 
time_t mktime( struct tm *arg );
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Renormalizes local calendar time expressed as a struct tm object and also converts it to time since epoch as a time_t object. arg->tm_wday and arg->tm_yday are ignored. The values in arg are not checked for being out of range.

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A negative value of arg->tm_isdst causes mktime to attempt to determine if Daylight Saving Time was in effect in the specified time.

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If the conversion to time_t is successful, the arg object is modified. All fields of arg are updated to fit their proper ranges. arg->tm_wday and arg->tm_yday are recalculated using information available in other fields.

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Parameters

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arg - pointer to a tm object specifying local calendar time to convert

Return value

time since epoch as a time_t object on success, or -1 if arg cannot be represented as a time_t object (POSIX also requires EOVERFLOW to be stored in errno in this case).

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Notes

If the struct tm object was obtained from POSIX strptime or equivalent function, the value of tm_isdst is indeterminate, and needs to be set explicitly before calling mktime.

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Example

#define _POSIX_C_SOURCE 200112L // for setenv on gcc
-#include <stdlib.h>
-#include <stdio.h>
-#include <time.h>
- 
-int main(void)
-{
-    setenv("TZ", "/usr/share/zoneinfo/America/New_York", 1); // POSIX-specific
- 
-    struct tm tm = *localtime(&(time_t){time(NULL)});
-    printf("Today is           %s", asctime(&tm));
-    printf("(DST is %s)\n", tm.tm_isdst ? "in effect" : "not in effect");
-    tm.tm_mon -= 100;  // tm_mon is now outside its normal range
-    mktime(&tm);       // tm_isdst is not set to -1; today's DST status is used
-    printf("100 months ago was %s", asctime(&tm));
-    printf("(DST was %s)\n", tm.tm_isdst ? "in effect" : "not in effect");
-}

Possible output:

-
Today is           Fri Apr 22 11:53:36 2016
-(DST is in effect)
-100 months ago was Sat Dec 22 10:53:36 2007
-(DST was not in effect)

References

See also

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-
(C23)(C11)
 converts time since epoch to calendar time expressed as local time
(function)
C++ documentation for mktime
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- © cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
- https://en.cppreference.com/w/c/chrono/mktime -

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