man3/OPENSSL_LH_COMPFUNC.pod: clarifications and updates.

Reviewed-by: Paul Dale <[email protected]>
Reviewed-by: Rich Salz <[email protected]>
(Merged from openssl#6786)

doc/man3/OPENSSL_LH_COMPFUNC.pod

@@ -18,7 +18,7 @@ lh_TYPE_doall, lh_TYPE_doall_arg, lh_TYPE_error - dynamic hash table
 
  DECLARE_LHASH_OF(TYPE);
 
- LHASH *lh_TYPE_new();
+ LHASH *lh_TYPE_new(OPENSSL_LH_HASHFUNC hash, OPENSSL_LH_COMPFUNC compare);
  void lh_TYPE_free(LHASH_OF(TYPE) *table);
 
  TYPE *lh_TYPE_insert(LHASH_OF(TYPE) *table, TYPE *data);
@@ -27,7 +27,7 @@ lh_TYPE_doall, lh_TYPE_doall_arg, lh_TYPE_error - dynamic hash table
 
  void lh_TYPE_doall(LHASH_OF(TYPE) *table, OPENSSL_LH_DOALL_FUNC func);
  void lh_TYPE_doall_arg(LHASH_OF(TYPE) *table, OPENSSL_LH_DOALL_FUNCARG func,
-          TYPE, TYPE *arg);
+                        TYPE *arg);
 
  int lh_TYPE_error(LHASH_OF(TYPE) *table);
 
@@ -171,25 +171,18 @@ lh_TYPE_retrieve() returns the hash table entry if it has been found,
 B<NULL> otherwise.
 
 lh_TYPE_error() returns 1 if an error occurred in the last operation, 0
-otherwise.
+otherwise. It's meaningful only after non-retrieve operations.
 
 lh_TYPE_free(), lh_TYPE_doall() and lh_TYPE_doall_arg() return no values.
 
 =head1 NOTE
 
-The various LHASH macros and callback types exist to make it possible
-to write type-checked code without resorting to function-prototype
-casting - an evil that makes application code much harder to
-audit/verify and also opens the window of opportunity for stack
-corruption and other hard-to-find bugs.  It also, apparently, violates
-ANSI-C.
-
-The LHASH code is not thread safe. All updating operations must be
-performed under a write lock. All retrieve operations should be performed
-under a read lock, I<unless> accurate usage statistics are desired.
-In which case, a write lock should be used for retrieve operations
-as well.  For output of the usage statistics, using the functions from
-L<OPENSSL_LH_stats(3)>, a read lock suffices.
+The LHASH code is not thread safe. All updating operations, as well as
+lh_TYPE_error call must be performed under a write lock. All retrieve
+operations should be performed under a read lock, I<unless> accurate
+usage statistics are desired. In which case, a write lock should be used
+for retrieve operations as well. For output of the usage statistics,
+using the functions from L<OPENSSL_LH_stats(3)>, a read lock suffices.
 
 The LHASH code regards table entries as constant data.  As such, it
 internally represents lh_insert()'d items with a "const void *"