$regerrstr
Returns the error string provided by the regular expression library for a failed evaluation.

1: \ at end of pattern
2: \c at end of pattern
3: unrecognized character follows \
4: numbers out of order in {} quantifier
5: number too big in {} quantifier
6: missing terminating ] for character class
7: invalid escape sequence in character class
8: range out of order in character class
9: nothing to repeat
10: [this code is not in use]
11: internal error: unexpected repeat
12: unrecognized character after (? or (?-
13: POSIX named classes are supported only within a class
14: missing )
15: reference to non-existent subpattern
16: erroffset passed as NULL
17: unknown option bit(s) set
18: missing ) after comment
19: [this code is not in use]
20: regular expression is too large
21: failed to get memory
22: unmatched parentheses
23: internal error: code overflow
24: unrecognized character after (?<
25: lookbehind assertion is not fixed length
26: malformed number or name after (?(
27: conditional group contains more than two branches
28: assertion expected after (?(
29: (?R or (?[+-]digits must be followed by )
30: unknown POSIX class name
31: POSIX collating elements are not supported
32: this version of PCRE is compiled without UTF support
33: [this code is not in use]
34: character value in \x{} or \o{} is too large
35: invalid condition (?(0)
36: \C not allowed in lookbehind assertion
37: PCRE does not support \L, \l, \N{name}, \U, or \u
38: number after (?C is > 255
39: closing ) for (?C expected
40: recursive call could loop indefinitely
41: unrecognized character after (?P
42: syntax error in subpattern name (missing terminator)
43: two named subpatterns have the same name
44: invalid UTF-8 string (specifically UTF-8)
45: support for \P, \p, and \X has not been compiled
46: malformed \P or \p sequence
47: unknown property name after \P or \p
48: subpattern name is too long (maximum 32 characters)
49: too many named subpatterns (maximum 10000)
50: [this code is not in use]
51: octal value is greater than \377 in 8-bit non-UTF-8 mode
52: internal error: overran compiling workspace
53: internal error: previously-checked referenced subpattern not found
54: DEFINE group contains more than one branch
55: repeating a DEFINE group is not allowed
56: inconsistent NEWLINE options
57: \g is not followed by a braced, angle-bracketed, or quoted name/number or by a plain number
58: a numbered reference must not be zero
59: an argument is not allowed for (*ACCEPT), (*FAIL), or (*COMMIT)
60: (*VERB) not recognized or malformed
61: number is too big
62: subpattern name expected
63: digit expected after (?+
64: ] is an invalid data character in JavaScript compatibility mode
65: different names for subpatterns of the same number are not allowed
66: (*MARK) must have an argument
67: this version of PCRE is not compiled with Unicode property support
68: \c must be followed by an ASCII character
69: \k is not followed by a braced, angle-bracketed, or quoted name
70: internal error: unknown opcode in find_fixedlength()
71: \N is not supported in a class
72: too many forward references
73: disallowed Unicode code point (>= 0xd800 && <= 0xdfff)
74: invalid UTF-16 string (specifically UTF-16)
75: name is too long in (*MARK), (*PRUNE), (*SKIP), or (*THEN)
76: character value in \u.... sequence is too large
77: invalid UTF-32 string (specifically UTF-32)
78: setting UTF is disabled by the application
79: non-hex character in \x{} (closing brace missing?)
80: non-octal character in \o{} (closing brace missing?)
81: missing opening brace after \o
82: parentheses are too deeply nested
83: invalid range in character class
84: group name must start with a non-digit
85: parentheses are too deeply nested (stack check)

//echo -a $regex(deneme,/denem(e){30000}/) - $regerrstr
-
Sonuç: 0 - regular expression is too large (Parantez içindeki değerin regex için çok büyük olduğu uyarısı)

//echo -a $regex(deneme,/den\x{65}me) - $regerrstr
Sonuç: \x65 veya \x{65} e karakteri ile eşleştiği için herhangi bir hata vermedi
-
//echo -a $regex(deneme,/den\x{65me) - $regerrstr
Sonuç: 0 - non-hex character in \x{} (closing brace missing?) - Parantez Kapanmadığı için hex karakteri tanımlayamadı ve hata verdi.

//echo -a $regex(deneme,/den[eme) - $regerrstr 
Sonuç: 0 - missing terminating ] for character class

//echo -a $regex(deneme,/den\Lme/) - $regerrstr
//echo -a $regex(deneme,/den\Ume/) - $regerrstr
Sonuç: 0 - PCRE does not support \L, \l, \N{name}, \U, or \u

//echo -a $regex(deneme,/deneme\/) - $regerrstr
Sonuç: 0 - \ at end of pattern

Doğru:   //echo -a $regex(denemee,/denem(e)\1/) - $regerrstr 
Yanlış:  //echo -a $regex(denemee,/denem(e)\2/) - $regerrstr
Sonuç:   0 - reference to non-existent subpattern