Improve interfaces to substring functions, and fix bugs.

git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@173 6239d852-aaf2-0410-a92c-79f79f948069

1 files changed, 10 insertions, 2 deletions

diff --git a/doc/pcre2_substring_copy_byname.3 b/doc/pcre2_substring_copy_byname.3
index 84d5517..5c8d075 100644
--- a/doc/pcre2_substring_copy_byname.3
+++ b/doc/pcre2_substring_copy_byname.3
@@ -24,8 +24,16 @@ by name, into a given buffer. The arguments are:
 .sp
 The \fIbufflen\fP variable is updated to contain the length of the extracted
 string, excluding the trailing zero. The yield of the function is zero for
-success, PCRE2_ERROR_NOMEMORY if the buffer is too small, or
-PCRE2_ERROR_NOSUBSTRING if the string name is invalid.
+success or one of the following error numbers:
+.sp
+  PCRE2_ERROR_NOSUBSTRING   there are no groups of that name
+  PCRE2_ERROR_UNAVAILBLE    the ovector was too small for that group
+  PCRE2_ERROR_UNSET         the group did not participate in the match
+  PCRE2_ERROR_NOMEMORY      the buffer is not big enough   
+.sp
+If there is more than one group with the given name, the first one that is set 
+is returned. In this situation PCRE2_ERROR_UNSET means that no group with the 
+given name was set.
 .P
 There is a complete description of the PCRE2 native API in the
 .\" HREF