- 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><A HREF="regcomp.3x.html">regcomp(3x)</A></STRONG> and
- <STRONG><A HREF="regexec.3x.html">regexec(3x)</A></STRONG>. Please notice that the regular expres-
- sion 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]* *$" which is good for leading
- and trailing spaces around the digits.
+ Regular expression data. Requires a regular expression <STRONG>(char</STRONG> <STRONG>*)</STRONG>
+ third argument. The data is valid if the regular expression
+ matches it.
+
+ Regular expressions are in the format of <STRONG>regcomp</STRONG> and <STRONG>regexec</STRONG>.
+
+ The regular expression must match the whole field. If you have
+ for example, an eight character wide field, a regular expression
+ "^[0-9]*$" 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.