Public/libcron
1
0
Fork 0
mirror of https://github.com/PerMalmberg/libcron.git synced 2025-06-30 16:02:57 -05:00
Code Issues Packages Projects Releases Wiki Activity

Updated README.

Browse Source 
Added tests.
Made use of ? mandatory for DoM/DoW.
This commit is contained in:
Per Malmberg
2018-03-11 18:45:27 +01:00
parent 9d7134c527
commit d7c17be4d1
7 changed files with 182 additions and 111 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
README.md
View File

@ -1,2 +1,62 @@
# libcron
A C++ scheduling library using cron formatting.
# Supported formatting
This implementation supports cron format, as specified below.
Each schedule expression conststs of 6 parts, all mandatory. However, if 'day of month' specifies specific days, then 'day of week' is ignored.
```text
┌──────────────seconds (0 - 59)
│ ┌───────────── minute (0 - 59)
│ │ ┌───────────── hour (0 - 23)
│ │ │ ┌───────────── day of month (1 - 31)
│ │ │ │ ┌───────────── month (1 - 12)
│ │ │ │ │ ┌───────────── day of week (0 - 6) (Sunday to Saturday)
│ │ │ │ │ │
│ │ │ │ │ │
│ │ │ │ │ │
* * * * * *
```
* Allowed formats:
* Special characters: '*', meaning the entire range.
* '?' used to ignore day of month/day of week as noted below.
* Ranges: 1,2,4-6
* Result: 1,2,4,5,6
* Steps: n/m, where n is the start and m is the step.
* `1/2` yields 1,3,5,7...<max>
* `5/3` yields 5,8,11,14...<max>
* `*/2` yields Result: 1,3,5,7...<max>
* Reversed ranges:
* `0 0 23-2 * * *`, meaning top of each minute and hour, of hours, 23, 0, 1 and 2, every day.
* Compare to `0 0 2-23 * * *` which means top of each minute and hour, of hours, 2,3...21,22,23 every day.
For `month`, these (case insensitive) strings can be used instead of numbers: `JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC`.
Example: `JAN,MAR,SEP-NOV`
For `day of week`, these (case insensitive) strings can be used instead of numbers: `SUN, MON, TUE, WED, THU, FRI, SAT`.
Example: `MON-THU,SAT`
Each part is separated by one or more whitespaces. It is thus important to keep whitespaces out of the respective parts.
* Valid:
* 0,3,40-50 * * * * ?
* Invalid:
* 0, 3, 40-50 * * * * ?
`Day of month` and `day of week` are mutually exclusive so one of them must at always be ignored using
the '?'-character unless one field already is something other than '*'.
# Examples
|Expression | Meaning
| --- | --- |
| * * * * * ? | Every second
|0 0 12 * * MON-FRI | Every Weekday at noon
|0 0 12 1/2 * ? | Every 2 days, starting on the 1st at noon
| 0 0 */12 ? * * | Every twelve hours