I have the following line in a php file
if(preg_match("!\oa!", $id)){
Until about 2 months ago this worked normally but started to give this error
Warning: preg_match () [function.preg-match]: Compilation failed: missing opening brace after \ o at offset
Can anyone tell me what's going on? I used some regular expression validators online and did not return any errors.
It's probably a bug in the PCRE library version you use , upgrade to the latest version.
As can be seen in the changelog , item 32 :
Error messages for syntax errors following \gand\kwere giving inaccurate offsets in the pattern.
The error can be seen in this example that uses version 8.35:
echo PCRE_VERSION; // 8.35 2014-04-04
var_dump(preg_match('/\k/', 'foo'));
// \k is not followed by a braced, angle-bracketed, or quoted name at offset 2
var_dump(preg_match('/\g/', 'foo'));
// a numbered reference must not be zero at offset 1
An alternative is to escape \k , \g and in your case \o with a double inverse bar \ :
$id = "\oa";
if(preg_match("!\\oa!", $id)) {
echo "Match!";
} else {
echo "No match.";
}