$dateadd function

$dateadd(date,days,months,years)

The $dateadd function returns the date that is days, months, years after date (or before, if any of them are negative). The date is returned in the standard internal format yyyymmdd: 4-digit year, 2-digit month, 2-digit day of the month.

The days, months, years parameters are optional; you may leave them empty if you don't need them. However, you must insert commas as necessary to indicate which of the three fields you are using. Some examples:

• $dateadd(date,days) to add a number of days;
• $dateadd(date,,months) to add a number of months;
• $dateadd(date,,,years) to add a number of years;
• $dateadd(date,days,,years) to add a number of days and years.

Tip: To add or subtract days, months, or years from the current date, you can use the $datenow function.

Windows Installer does not support symbolic functions; if you use this function during an MSI build, you will get diagnostic message BLD:U0010 and the result is undefined.

Parameters

All parameters may contain symbolic references; these are resolved before the function is applied. See Examples below.

date

Starting date in the format yyyymmdd.

days

Difference in days, either positive (for a later date) or negative (for an earlier date). This parameter is optional.

months

Difference in months, either positive (for a later date) or negative (for an earlier date). This parameter is optional.

years

Difference in years, either positive (for a later date) or negative (for an earlier date). This parameter is optional.

Examples

Here are some usage examples for this function:

<$dateadd(<BuildDate>, 30)>

Returns the date 30 days after the installer was built.

Note: BuildDate is a standard variable. However, it is not saved in the installer's database by default, so you must set its Save for Tarma attribute to use it in the installer.

<$dateadd(<BuildDate>,,6)>

Returns the date six months after the installer was built.

<$dateadd(<BuildDate>,1,,1)>

Returns the date 1 year plus 1 day after the installer was built.

<InstallDate> > <$dateadd(<BuildDate>,,6)>

This is a conditional expression that returns True if the current installation date is more than 6 months after the installer's build date. You can use this type of condition, for example, to alert the user to possible new software releases. InstallDate is a standard variable.