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Address MicrosoftDocs/cpp-docs/issues/484 TZNAME_MAX obsolete (MicrosoftDocs#1506)
* Address MicrosoftDocs/cpp-docs/issues/484 TZNAME_MAX obsolete * Add comments to the sample * Update tzname-max.md - Clarify how to find the equivalent information.
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‎docs/c-runtime-library/reference/get-tzname.md‎

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---
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title: "_get_tzname | Microsoft Docs"
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ms.custom: ""
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ms.date: "11/04/2016"
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ms.date: "10/22/2018"
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ms.technology: ["cpp-standard-libraries"]
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ms.topic: "reference"
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apiname: ["_get_tzname"]
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*index*<br/>
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The index of one of the two time zone names to retrieve.
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|*index*|Contents of *timeZoneName*|*timeZoneName* default value|
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|-|-|-|
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|0|Time zone name|"PST"|
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|1|Daylight standard time zone name|"PDT"|
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|> 1 or < 0|**errno** set to **EINVAL**|not modified|
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Unless the values are explicitly changed during run time, the default values are "PST" and "PDT" respectively.
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## Return Value
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Zero if successful, otherwise an **errno** type value.
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## Remarks
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The **_get_tzname** function retrieves the character string representation of the time zone name or the daylight standard time zone name (DST) into the address of *timeZoneName* depending on the index value, along with the size of the string in *pReturnValue*. If *timeZoneName* is **NULL** and *sizeInBytes* is zero, just the size of the string of either time zone in bytes is returned in *pReturnValue*. The index values must be either 0 for standard time zone or 1 for daylight standard time zone; any other values of index have undetermined results.
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The **_get_tzname** function retrieves the character string representation of the current time zone name or the daylight standard time zone name (DST) into the address of *timeZoneName* depending on the index value, along with the size of the string in *pReturnValue*. If *timeZoneName* is **NULL** and *sizeInBytes* is zero, the size of the string required to hold the specified time zone and a terminating null in bytes is returned in *pReturnValue*. The index values must be either 0 for standard time zone or 1 for daylight standard time zone; any other values of *index* have undetermined results.
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### Index values
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## Example
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|*index*|Contents of *timeZoneName*|*timeZoneName* default value|
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|-------------|--------------------------------|----------------------------------|
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|0|Time zone name|"PST"|
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|1|Daylight standard time zone name|"PDT"|
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|> 1 or < 0|**errno** set to **EINVAL**|not modified|
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This sample calls **_get_tzname** to get the required buffer size to display the current Daylight standard time zone name, allocates a buffer of that size, calls **_get_tzname** again to load the name in the buffer, and prints it to the console.
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Unless the values are explicitly changed during run time, the default values are "PST" and "PDT" respectively. The sizes of these character arrays are governed by **TZNAME_MAX** value.
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```C
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// crt_get_tzname.c
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// Compile by using: cl /W4 crt_get_tzname.c
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#include <stdio.h>
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#include <time.h>
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#include <malloc.h>
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enum TZINDEX {
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STD,
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DST
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};
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int main()
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{
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size_t tznameSize = 0;
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char * tznameBuffer = NULL;
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// Get the size of buffer required to hold DST time zone name
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if (_get_tzname(&tznameSize, NULL, 0, DST))
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return 1; // Return an error value if it failed
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// Allocate a buffer for the name
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if (NULL == (tznameBuffer = (char *)(malloc(tznameSize))))
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return 2; // Return an error value if it failed
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// Load the name in the buffer
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if (_get_tzname(&tznameSize, tznameBuffer, tznameSize, DST))
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return 3; // Return an error value if it failed
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printf_s("The current Daylight standard time zone name is %s.\n", tznameBuffer);
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return 0;
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}
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```
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### Output
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```Output
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The current Daylight standard time zone name is PDT.
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```
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## Requirements
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[_get_daylight](get-daylight.md)<br/>
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[_get_dstbias](get-dstbias.md)<br/>
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[_get_timezone](get-timezone.md)<br/>
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[TZNAME_MAX](../../c-runtime-library/tzname-max.md)<br/>

‎docs/c-runtime-library/tzname-max.md‎

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title: "TZNAME_MAX | Microsoft Docs"
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ms.custom: ""
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ms.date: "11/04/2016"
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ms.date: "10/22/2018"
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ms.technology: ["cpp-standard-libraries"]
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ms.topic: "conceptual"
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f1_keywords: ["TZNAME_MAX"]
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---
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# TZNAME_MAX
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The maximum permissible string length for a time zone name variable.
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**Obsolete**. The maximum permissible string length for a time zone name variable. This macro was defined in \<limits.h> in Visual Studio 2012 and earlier versions. It is not defined in Visual Studio 2013 and later versions. To get the length required to hold the current time zone name, use [_get_tzname](../c-runtime-library/reference/get-tzname.md).
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## Syntax
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[Environmental Constants](../c-runtime-library/environmental-constants.md)<br/>
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[Global Constants](../c-runtime-library/global-constants.md)<br/>
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[_get_tzname](../c-runtime-library/reference/get-tzname.md)
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[_get_tzname](../c-runtime-library/reference/get-tzname.md)

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