diff --git a/src/common/stringutil.cc b/src/common/stringutil.cc
index ef4aa65..df0ca1e 100644
--- a/src/common/stringutil.cc
+++ b/src/common/stringutil.cc
@@ -440,7 +440,14 @@ Expected results:
 
 long opp_strtol(const char *s, char **endptr)
 {
-    long d = strtol(s, endptr, 0);
+    // accept decimal and hex numbers (0x), but ignore leading zero as octal prefix;
+    // C's octal notation is not explicit enough, and causes confusion e.g. with
+    // the runnumber-width configuration option (bug #232)
+    while (opp_isspace(*s))
+        s++;
+    bool ishex = (s[0]=='0' && opp_toupper(s[1])=='X') ||
+                 ((s[0]=='+' || s[0]=='-') && s[1]=='0' && opp_toupper(s[2])=='X');
+    long d = strtol(s, endptr, ishex ? 16 : 10);
     if ((d==LONG_MAX || d==LONG_MIN) && errno==ERANGE)
         throw opp_runtime_error("overflow converting `%s' to long", s);
     return d;
@@ -459,7 +466,14 @@ long opp_atol(const char *s)
 
 unsigned long opp_strtoul(const char *s, char **endptr)
 {
-    unsigned long d = strtoul(s, endptr, 0);
+    // accept decimal and hex numbers (0x), but ignore leading zero as octal prefix;
+    // C's octal notation is not explicit enough, and causes confusion e.g. with
+    // the runnumber-width configuration option (bug #232)
+    while (opp_isspace(*s))
+        s++;
+    bool ishex = (s[0]=='0' && opp_toupper(s[1])=='X') ||
+                 (s[0]=='+' && s[1]=='0' && opp_toupper(s[2])=='X');
+    unsigned long d = strtoul(s, endptr, ishex ? 16 : 10);
     if (d==ULONG_MAX && errno==ERANGE)
         throw opp_runtime_error("overflow converting `%s' to unsigned long", s);
     return d;
diff --git a/src/common/stringutil.h b/src/common/stringutil.h
index b204c74..3c724b6 100644
--- a/src/common/stringutil.h
+++ b/src/common/stringutil.h
@@ -209,28 +209,36 @@ COMMON_API std::string opp_join(const char *separator, const char *s1, const cha
 COMMON_API int strdictcmp(const char *s1, const char *s2);
 
 /**
- * Like the standard strtol() with base==0, but throws opp_runtime_error if an
- * overflow occurs during conversion.
+ * Like the standard strtol(), but throws opp_runtime_error if an overflow
+ * occurs during conversion. Accepts decimal and C-style hexadecimal
+ * notation, but not octal (leading zeroes are simply discarded and the number
+ * is interpreted as decimal).
  */
 COMMON_API long opp_strtol(const char *s, char **endptr);
 
 /**
  * Like the standard atol(), but throws opp_runtime_error if an overflow
  * occurs during conversion, or if there is (non-whitespace) trailing garbage
- * after the number.
+ * after the number. Accepts decimal and C-style hexadecimal notation, but not
+ * octal (leading zeroes are simply discarded and the number is interpreted as
+ * decimal).
  */
 COMMON_API long opp_atol(const char *s);
 
 /**
- * Like the standard strtoul() with base==0, but throws opp_runtime_error if an
- * overflow occurs during conversion.
+ * Like the standard strtoul(), but throws opp_runtime_error if an
+ * overflow occurs during conversion. Accepts decimal and C-style hexadecimal
+ * notation, but not octal (leading zeroes are simply discarded and the number
+ * is interpreted as decimal).
  */
 COMMON_API unsigned long opp_strtoul(const char *s, char **endptr);
 
 /**
  * Like the standard atol(), but for unsigned long, and throws opp_runtime_error
  * if an overflow occurs during conversion, or if there is (non-whitespace)
- * trailing garbage after the number.
+ * trailing garbage after the number. Accepts decimal and C-style hexadecimal
+ * notation, but not octal (leading zeroes are simply discarded and the number
+ * is interpreted as decimal).
  */
 COMMON_API unsigned long opp_atoul(const char *s);