#### 3.15.2 Validation Warnings

Some possible problems with SCCS files are not definitively errors. In these situations, `val` will emit a warning message but the validation will not fail (that is, if there are no other problems the return value will be zero). An explanation of the possible warnings appears below.

WARNING: date for version 1.1 is later than the date for version 1.2

  This message indicates that a delta exists in the history file where the “parent” delta has a delta creation time which is later than the creation time of the “child” delta. This is a warning only because the delta creation time is measured in local time, and so if two developers with different time locale settings both edit the file in a short period of time, this can happen. If all the developers who create deltas in a history file use the same timezone settings, this should not happen.

  Some versions of SCCS, but not CSSC exhibit a peculiar behaviour in these circumstances, and do not include in the gotten file any lines apparently inserted after the date of the delta which has been selected. This applies to `get` but more importantly also applies to the temporary file generated by DELTA which is compared with the working copy of tyhe file. Once this has happened there is no way to recover from this problem other than to hand-edit the SCCS file.

Unknown special comment intro

  This message is displayed when a “c” control line is seen in the body of the SCCS file in which the initial “c” is not followed immediately by a space. Lines of this type are used as an extension mechanism by some other SCCS implementations, notably the BitKeeper suite, and CSSC knows about this, but if it sees a construction it doesn’t recognise, this warning is issued.

The ’y’ flag specifies a keyword letter ’X’ but %X% is not a recognised SCCS keyword

  This message is displayed when the ‘`y`’ flag of the SCCS file is set to a value which includes a keyword letter which is not known. This is harmless unless you intended to set the flag to some other value. Flags.