diff --git a/ChangeLog b/ChangeLog
index 57c8999..161b4e0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -132,6 +132,8 @@ a warning for "fileno" unless -std=gnu99 us used.
 33. A lookbehind assertion within a set of mutually recursive subpatterns could 
 provoke a buffer overflow. This bug was discovered by the LLVM fuzzer.
 
+34. Give an error for an empty subpattern name such as (?'').
+
 
 Version 10.10 06-March-2015
 ---------------------------
diff --git a/src/pcre2_compile.c b/src/pcre2_compile.c
index 07b23c8..7719d88 100644
--- a/src/pcre2_compile.c
+++ b/src/pcre2_compile.c
@@ -5814,13 +5814,19 @@ for (;; ptr++)
           {
           named_group *ng;
           uint32_t number = cb->bracount + 1;
-
+          
           if (*ptr != (PCRE2_UCHAR)terminator)
             {
             *errorcodeptr = ERR42;
             goto FAILED;
             }
 
+          if (namelen == 0)
+            {
+            *errorcodeptr = ERR62;
+            goto FAILED;
+            }
+
           if (cb->names_found >= MAX_NAME_COUNT)
             {
             *errorcodeptr = ERR49;
diff --git a/testdata/testinput2 b/testdata/testinput2
index a00a3d8..4badd3f 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -4298,14 +4298,16 @@ a random value. /Ix
 
 /\V\x85\9*+((?2)\3++()2)*:2/
 
-/(((?(R)){0,2}) (?''((?'R')((?'R')))))/dupnames
+/(((?(R)){0,2}) (?'x'((?'R')((?'R')))))/dupnames
 
-/(((?(X)){0,2}) (?''((?'X')((?'X')))))/dupnames
+/(((?(X)){0,2}) (?'x'((?'X')((?'X')))))/dupnames
 
-/(((?(R)){0,2}) (?''((?'X')((?'R')))))/
+/(((?(R)){0,2}) (?'x'((?'X')((?'R')))))/
 
 "(?J)(?'d'(?'d'\g{d}))"
 
 "(?=!((?2)(?))({8(?<=(?1){29}8bbbb\x16\xd\xc6^($(\xa9H4){4}h}?1)B))\x15')"
 
+/A(?'')Z/
+
 # End of testinput2 
diff --git a/testdata/testinput5 b/testdata/testinput5
index 9ab5f41..7e2ba45 100644
--- a/testdata/testinput5
+++ b/testdata/testinput5
@@ -1647,8 +1647,8 @@
 /(?<=\K\x{17f})/altglobal,utf,aftertext
     \x{17f}\x{17f}\x{17f}\x{17f}\x{17f}
 
-"\xa\xf<(.\pZ*\P{Xwd}+^\xa8\3'3yq.::?(?J:()\xd1+!~:3'(8?:)':(?'d'(?'d'^u]!.+.+\\A\Ah(n+?9){7}+\K;(?''u'(?'c'(?'z'(?<y>\xb::\xf0'|\xd3(\xae?'w(z\x8?P>l)\x8?P>a)'\H\R\xd1+!!~:3'(?:h$N{26875}\W+?\\=D{2}\x89(?i:Uy0\N({2\xa(\v\x85*){y*\A(()\p{L}+?\P{^Xan}'+?\xff\+pS\?|).{;y*\A(()\p{L}+?\8}\d?1(|)(/1){7}.+[Lp{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(\xbf(R))\x8a\X*?\x8a\xb\xd1^9\3*+(\xc1,\k'R'\xb4)\xcc(z\z(?J)(?''\x1b(\xb\xd1^9\?'3*+P{^Xan}+?\xff\+(\xc1.]k+\xb'Pm'\xb4)\xcc4f\xa7'\xd1V(?i:U,{2,2})'(?''))?-%--\x95$9*\4'|\xd1(\x9c''%\x94$9)#(?'R')3\x7?('P\xed7'\xa8\xb1^u\xeaw\1\0\0\(|(?1){7}.+[\p{Me}].\s\xdcC*^\x14?(?(<y>))(?<!^)$C((;*?(R*?))+(?(R)\x8a\X*?\x8a\xb\xd1^9\3*+|(\xc1,\k'R'\xb4)\xcc! z)\z(?JJ)(?'';(\xb\xd1^9\?'3*+(\xc1.]k+\xb'Pm'\xb4))':(?'d')(?'RD'(d')|)|$)'|(?<x>\g{d});\g{x}\x11\g{d}\x81\|$((?''\'X'(?'W''\x92()'9'\x83*))\xba*\!?^ <){)':;\xcc4'\xd1'(?''28))?-%--\x95$9*\4'|\xd1((''e\x94*$9:)*#(?'R')3)\x7?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+0!~:(?)'d'E:yD!\s(?'R'\x1e;\x10:U))|'\x9g!\xb0*){)\\x16:;()\x1e\x10\x87*:(?<y>)\xd1+!~:(?)'}'\d'E:yD!\s(?'R'\x1e;\x10:U))|'))|)g!\xb0*R+9{29+)#(?'P'})*?pS\{3,}\x85,{0,}l{*UTF)(\xe{7}){3722,{9,}d{2,?|))|{)\(A?&d}}{\xa,}2}){3,}7,l{)22}(,}l:7{2,4}}29\x19+)#?'P'})*v?))\x5"
+"\xa\xf<(.\pZ*\P{Xwd}+^\xa8\3'3yq.::?(?J:()\xd1+!~:3'(8?:)':(?'d'(?'d'^u]!.+.+\\A\Ah(n+?9){7}+\K;(?'X'u'(?'c'(?'z'(?<y>\xb::\xf0'|\xd3(\xae?'w(z\x8?P>l)\x8?P>a)'\H\R\xd1+!!~:3'(?:h$N{26875}\W+?\\=D{2}\x89(?i:Uy0\N({2\xa(\v\x85*){y*\A(()\p{L}+?\P{^Xan}'+?\xff\+pS\?|).{;y*\A(()\p{L}+?\8}\d?1(|)(/1){7}.+[Lp{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(\xbf(R))\x8a\X*?\x8a\xb\xd1^9\3*+(\xc1,\k'R'\xb4)\xcc(z\z(?J)(?'X'\x1b(\xb\xd1^9\?'3*+P{^Xan}+?\xff\+(\xc1.]k+\xb'Pm'\xb4)\xcc4f\xa7'\xd1V(?i:U,{2,2})'(?'X'))?-%--\x95$9*\4'|\xd1(\x9c''%\x94$9)#(?'R')3\x7?('P\xed7'\xa8\xb1^u\xeaw\1\0\0\(|(?1){7}.+[\p{Me}].\s\xdcC*^\x14?(?(<y>))(?<!^)$C((;*?(R*?))+(?(R)\x8a\X*?\x8a\xb\xd1^9\3*+|(\xc1,\k'R'\xb4)\xcc! z)\z(?JJ)(?'X';(\xb\xd1^9\?'3*+(\xc1.]k+\xb'Pm'\xb4))':(?'d')(?'RD'(d')|)|$)'|(?<x>\g{d});\g{x}\x11\g{d}\x81\|$((?'X'\'X'(?'W''\x92()'9'\x83*))\xba*\!?^ <){)':;\xcc4'\xd1'(?'X'28))?-%--\x95$9*\4'|\xd1((''e\x94*$9:)*#(?'R')3)\x7?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+0!~:(?)'d'E:yD!\s(?'R'\x1e;\x10:U))|'\x9g!\xb0*){)\\x16:;()\x1e\x10\x87*:(?<y>)\xd1+!~:(?)'}'\d'E:yD!\s(?'R'\x1e;\x10:U))|'))|)g!\xb0*R+9{29+)#(?'P'})*?pS\{3,}\x85,{0,}l{*UTF)(\xe{7}){3722,{9,}d{2,?|))|{)\(A?&d}}{\xa,}2}){3,}7,l{)22}(,}l:7{2,4}}29\x19+)#?'P'})*v?))\x5"
 
-/$(&.+[\p{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(?(R)){0,6}?|){12\x8a\X*?\x8a\x0b\xd1^9\3*+(\xc1,\k'P'\xb4)\xcc(z\z(?JJ)(?''8};(\x0b\xd1^9\?'3*+(\xc1.]k+\x0b'Pm'\xb4\xcc4'\xd1'(?''))?-%--\x95$9*\4'|\xd1(''%\x95*$9)#(?'R')3\x07?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+!~:(?)''(d'E:yD!\s(?'R'\x1e;\x10:U))|')g!\xb0*){29+))#(?'P'})*?/
+/$(&.+[\p{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(?(R)){0,6}?|){12\x8a\X*?\x8a\x0b\xd1^9\3*+(\xc1,\k'P'\xb4)\xcc(z\z(?JJ)(?'X'8};(\x0b\xd1^9\?'3*+(\xc1.]k+\x0b'Pm'\xb4\xcc4'\xd1'(?'X'))?-%--\x95$9*\4'|\xd1(''%\x95*$9)#(?'R')3\x07?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+!~:(?)''(d'E:yD!\s(?'R'\x1e;\x10:U))|')g!\xb0*){29+))#(?'P'})*?/
 
 # End of testinput5 
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index 51a04a1..a98e277 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -14397,15 +14397,18 @@ Failed: error 115 at offset 22: reference to non-existent subpattern
 /\V\x85\9*+((?2)\3++()2)*:2/
 Failed: error 115 at offset 26: reference to non-existent subpattern
 
-/(((?(R)){0,2}) (?''((?'R')((?'R')))))/dupnames
+/(((?(R)){0,2}) (?'x'((?'R')((?'R')))))/dupnames
 
-/(((?(X)){0,2}) (?''((?'X')((?'X')))))/dupnames
+/(((?(X)){0,2}) (?'x'((?'X')((?'X')))))/dupnames
 
-/(((?(R)){0,2}) (?''((?'X')((?'R')))))/
+/(((?(R)){0,2}) (?'x'((?'X')((?'R')))))/
 
 "(?J)(?'d'(?'d'\g{d}))"
 
 "(?=!((?2)(?))({8(?<=(?1){29}8bbbb\x16\xd\xc6^($(\xa9H4){4}h}?1)B))\x15')"
 Failed: error 125 at offset 72: lookbehind assertion is not fixed length
 
+/A(?'')Z/
+Failed: error 162 at offset 4: subpattern name expected
+
 # End of testinput2 
diff --git a/testdata/testoutput5 b/testdata/testoutput5
index d85f909..a99c12b 100644
--- a/testdata/testoutput5
+++ b/testdata/testoutput5
@@ -4045,9 +4045,9 @@ Failed: error 140 at offset 11: recursion could loop indefinitely
  0: \x{17f}
  0+ 
 
-"\xa\xf<(.\pZ*\P{Xwd}+^\xa8\3'3yq.::?(?J:()\xd1+!~:3'(8?:)':(?'d'(?'d'^u]!.+.+\\A\Ah(n+?9){7}+\K;(?''u'(?'c'(?'z'(?<y>\xb::\xf0'|\xd3(\xae?'w(z\x8?P>l)\x8?P>a)'\H\R\xd1+!!~:3'(?:h$N{26875}\W+?\\=D{2}\x89(?i:Uy0\N({2\xa(\v\x85*){y*\A(()\p{L}+?\P{^Xan}'+?\xff\+pS\?|).{;y*\A(()\p{L}+?\8}\d?1(|)(/1){7}.+[Lp{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(\xbf(R))\x8a\X*?\x8a\xb\xd1^9\3*+(\xc1,\k'R'\xb4)\xcc(z\z(?J)(?''\x1b(\xb\xd1^9\?'3*+P{^Xan}+?\xff\+(\xc1.]k+\xb'Pm'\xb4)\xcc4f\xa7'\xd1V(?i:U,{2,2})'(?''))?-%--\x95$9*\4'|\xd1(\x9c''%\x94$9)#(?'R')3\x7?('P\xed7'\xa8\xb1^u\xeaw\1\0\0\(|(?1){7}.+[\p{Me}].\s\xdcC*^\x14?(?(<y>))(?<!^)$C((;*?(R*?))+(?(R)\x8a\X*?\x8a\xb\xd1^9\3*+|(\xc1,\k'R'\xb4)\xcc! z)\z(?JJ)(?'';(\xb\xd1^9\?'3*+(\xc1.]k+\xb'Pm'\xb4))':(?'d')(?'RD'(d')|)|$)'|(?<x>\g{d});\g{x}\x11\g{d}\x81\|$((?''\'X'(?'W''\x92()'9'\x83*))\xba*\!?^ <){)':;\xcc4'\xd1'(?''28))?-%--\x95$9*\4'|\xd1((''e\x94*$9:)*#(?'R')3)\x7?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+0!~:(?)'d'E:yD!\s(?'R'\x1e;\x10:U))|'\x9g!\xb0*){)\\x16:;()\x1e\x10\x87*:(?<y>)\xd1+!~:(?)'}'\d'E:yD!\s(?'R'\x1e;\x10:U))|'))|)g!\xb0*R+9{29+)#(?'P'})*?pS\{3,}\x85,{0,}l{*UTF)(\xe{7}){3722,{9,}d{2,?|))|{)\(A?&d}}{\xa,}2}){3,}7,l{)22}(,}l:7{2,4}}29\x19+)#?'P'})*v?))\x5"
-Failed: error 122 at offset 1221: unmatched closing parenthesis
+"\xa\xf<(.\pZ*\P{Xwd}+^\xa8\3'3yq.::?(?J:()\xd1+!~:3'(8?:)':(?'d'(?'d'^u]!.+.+\\A\Ah(n+?9){7}+\K;(?'X'u'(?'c'(?'z'(?<y>\xb::\xf0'|\xd3(\xae?'w(z\x8?P>l)\x8?P>a)'\H\R\xd1+!!~:3'(?:h$N{26875}\W+?\\=D{2}\x89(?i:Uy0\N({2\xa(\v\x85*){y*\A(()\p{L}+?\P{^Xan}'+?\xff\+pS\?|).{;y*\A(()\p{L}+?\8}\d?1(|)(/1){7}.+[Lp{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(\xbf(R))\x8a\X*?\x8a\xb\xd1^9\3*+(\xc1,\k'R'\xb4)\xcc(z\z(?J)(?'X'\x1b(\xb\xd1^9\?'3*+P{^Xan}+?\xff\+(\xc1.]k+\xb'Pm'\xb4)\xcc4f\xa7'\xd1V(?i:U,{2,2})'(?'X'))?-%--\x95$9*\4'|\xd1(\x9c''%\x94$9)#(?'R')3\x7?('P\xed7'\xa8\xb1^u\xeaw\1\0\0\(|(?1){7}.+[\p{Me}].\s\xdcC*^\x14?(?(<y>))(?<!^)$C((;*?(R*?))+(?(R)\x8a\X*?\x8a\xb\xd1^9\3*+|(\xc1,\k'R'\xb4)\xcc! z)\z(?JJ)(?'X';(\xb\xd1^9\?'3*+(\xc1.]k+\xb'Pm'\xb4))':(?'d')(?'RD'(d')|)|$)'|(?<x>\g{d});\g{x}\x11\g{d}\x81\|$((?'X'\'X'(?'W''\x92()'9'\x83*))\xba*\!?^ <){)':;\xcc4'\xd1'(?'X'28))?-%--\x95$9*\4'|\xd1((''e\x94*$9:)*#(?'R')3)\x7?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+0!~:(?)'d'E:yD!\s(?'R'\x1e;\x10:U))|'\x9g!\xb0*){)\\x16:;()\x1e\x10\x87*:(?<y>)\xd1+!~:(?)'}'\d'E:yD!\s(?'R'\x1e;\x10:U))|'))|)g!\xb0*R+9{29+)#(?'P'})*?pS\{3,}\x85,{0,}l{*UTF)(\xe{7}){3722,{9,}d{2,?|))|{)\(A?&d}}{\xa,}2}){3,}7,l{)22}(,}l:7{2,4}}29\x19+)#?'P'})*v?))\x5"
+Failed: error 122 at offset 1227: unmatched closing parenthesis
 
-/$(&.+[\p{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(?(R)){0,6}?|){12\x8a\X*?\x8a\x0b\xd1^9\3*+(\xc1,\k'P'\xb4)\xcc(z\z(?JJ)(?''8};(\x0b\xd1^9\?'3*+(\xc1.]k+\x0b'Pm'\xb4\xcc4'\xd1'(?''))?-%--\x95$9*\4'|\xd1(''%\x95*$9)#(?'R')3\x07?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+!~:(?)''(d'E:yD!\s(?'R'\x1e;\x10:U))|')g!\xb0*){29+))#(?'P'})*?/
+/$(&.+[\p{Me}].\s\xdcC*?(?(<y>))(?<!^)$C((;*?(R))+(?(R)){0,6}?|){12\x8a\X*?\x8a\x0b\xd1^9\3*+(\xc1,\k'P'\xb4)\xcc(z\z(?JJ)(?'X'8};(\x0b\xd1^9\?'3*+(\xc1.]k+\x0b'Pm'\xb4\xcc4'\xd1'(?'X'))?-%--\x95$9*\4'|\xd1(''%\x95*$9)#(?'R')3\x07?('P\xed')\\x16:;()\x1e\x10*:(?<y>)\xd1+!~:(?)''(d'E:yD!\s(?'R'\x1e;\x10:U))|')g!\xb0*){29+))#(?'P'})*?/
 
 # End of testinput5