- Regular expression data. Requires a regular expres-
- sion <STRONG>(char</STRONG> <STRONG>*)</STRONG> third argument; the data is valid if
- the regular expression matches it. Regular expres-
- sions are in the format of <STRONG>regcomp</STRONG> and <STRONG>regexec</STRONG>.
- Please notice that the regular expression must match
- the whole field. If you have for example an eight
- character wide field, a regular expression "^[0-9]*$"
- always means that you have to fill all eight posi-
- tions with digits. If you want to allow fewer digits,
- you may use for example "^[0-9]* *$" which is good
- for trailing spaces (up to an empty field), or "^
- *[0-9]* *$" which is good for leading and trailing
- spaces around the digits.
+ Regular expression data. Requires a regular expression <STRONG>(char</STRONG> <STRONG>*)</STRONG>
+ third argument; the data is valid if the regular expression
+ matches it. Regular expressions are in the format of <STRONG>regcomp</STRONG> and
+ <STRONG>regexec</STRONG>. Please notice that the regular expression must match the
+ whole field. If you have for example an eight character wide
+ field, a regular expression "^[0-9]*$" always means that you have
+ to fill all eight positions with digits. If you want to allow
+ fewer digits, you may use for example "^[0-9]* *$" which is good
+ for trailing spaces (up to an empty field), or "^ *[0-9]* *$"
+ which is good for leading and trailing spaces around the digits.