Use GCC attribute warn_unsed_result for a few of the most important

[idzebra-moved-to-github.git] / include / idzebra / api.h

diff --git a/include/idzebra/api.h b/include/idzebra/api.h
index bb707cb..f91ed82 100644 (file)
--- a/include/idzebra/api.h
+++ b/include/idzebra/api.h
@@ -1,4 +1,4 @@
-/* $Id: api.h,v 1.28 2005-08-09 09:35:25 adam Exp $
+/* $Id: api.h,v 1.32 2006-03-31 15:58:03 adam Exp $
    Copyright (C) 1995-2005
    Index Data ApS
 
@@ -39,6 +39,19 @@ Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 
 YAZ_BEGIN_CDECL
 
+/*
+  expand GCC_ATTRIBUTE if GCC is in use. See :
+  http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
+*/
+
+#ifndef GCC_ATTRIBUTE
+#ifdef __GNUC__
+#define GCC_ATTRIBUTE(x) __attribute__ (x)
+#else
+#define GCC_ATTRIBUTE(x)
+#endif
+#endif
+
 typedef struct {
     int processed;
     int inserted;
@@ -84,7 +97,8 @@ typedef struct zebra_service *ZebraService;
     This function is a simplified version of zebra_start_res.
 */
 YAZ_EXPORT
-ZebraService zebra_start(const char *configName);
+ZebraService zebra_start(const char *configName
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 /** \fn ZebraService zebra_start_res(const char *configName, \
                                      Res def_res, Res over_res)
@@ -98,7 +112,8 @@ ZebraService zebra_start(const char *configName);
 */
 YAZ_EXPORT
 ZebraService zebra_start_res(const char *configName,
-                            Res def_res, Res over_res);
+                            Res def_res, Res over_res
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 /**
    \brief stops a Zebra service.
@@ -129,7 +144,8 @@ void zebra_filter_info(ZebraService zs, void *cd,
    one handle is sufficient 
 */
 YAZ_EXPORT
-ZebraHandle zebra_open(ZebraService zs);
+ZebraHandle zebra_open(ZebraService zs, Res res
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 /**
    \brief Destroys Zebra session handle.
@@ -168,14 +184,6 @@ char *zebra_errAdd(ZebraHandle zh);
 YAZ_EXPORT
 void zebra_result(ZebraHandle zh, int *code, char **addinfo);
 
-/** 
-    \brief Clears last error.
-    \param zh zebra session handle.
-*/
-YAZ_EXPORT
-void zebra_clearError(ZebraHandle zh);
-
-
 /**
    \brief Set limit before Zebra does approx hit count
    \param zh session handle
@@ -245,11 +253,39 @@ int zebra_deleteResultSet(ZebraHandle zh, int function,
                          int *statuses);
 
 
+/**
+   \brief returns number of term info terms assocaited with result set
+   \param zh session handle
+   \param setname result set name
+   \param num_terms number of terms returned in this integer
 
+   This function is used in conjunction with zebra_result_set_term_info.
+   If operation was successful, ZEBRA_OK is returned; otherwise
+   ZEBRA_FAIL is returned (typically non-existing setname)
+*/
 YAZ_EXPORT
 ZEBRA_RES zebra_result_set_term_no(ZebraHandle zh, const char *setname,
                                   int *num_terms);
 
+/**
+   \brief returns information about a term assocated with a result set
+   \param zh session handle
+   \param setname result set name
+   \param no the term we want to know about (0=first, 1=second,..)
+   \param count the number of occurrences of this term, aka hits (output) 
+   \param approx about hits: 0=exact,1=approx (output)
+   \param termbuf buffer for term string (intput, output)
+   \param termlen size of termbuf (input=max, output=actual length)
+   \param term_ref_id if non-NULL *term_ref_id holds term reference
+
+   Returns information about one search term associated with result set.
+   Use zebra_result_set_term_no to read total number of terms associated
+   with result set. If this function can not return information,
+   due to no out of range or bad result set name, ZEBRA_FAIL is
+   returned.
+   The passed termbuf must be able to hold at least *termlen characters.
+   Upon completion, *termlen holds actual length of search term.
+*/
 YAZ_EXPORT
 ZEBRA_RES zebra_result_set_term_info(ZebraHandle zh, const char *setname,
                                     int no, zint *count, int *approx,
@@ -359,10 +395,12 @@ ZEBRA_RES zebra_admin_exchange_record(ZebraHandle zh,
                                      int action);
 
 YAZ_EXPORT 
-ZEBRA_RES zebra_begin_trans(ZebraHandle zh, int rw);
+ZEBRA_RES zebra_begin_trans(ZebraHandle zh, int rw
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 YAZ_EXPORT
-ZEBRA_RES zebra_end_trans(ZebraHandle zh);
+ZEBRA_RES zebra_end_trans(ZebraHandle zh
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 YAZ_EXPORT
 ZEBRA_RES zebra_end_transaction(ZebraHandle zh,
@@ -408,24 +446,22 @@ ZEBRA_RES zebra_delete_record(ZebraHandle zh,
                              int force_update);
 
 YAZ_EXPORT 
-int zebra_resultSetTerms(ZebraHandle zh, const char *setname, 
-                        int no, zint *count, 
-                        int *type, char *out, size_t *len);
-
-YAZ_EXPORT 
 ZEBRA_RES zebra_sort(ZebraHandle zh, ODR stream,
                     int num_input_setnames,
                     const char **input_setnames,
                     const char *output_setname,
                     Z_SortKeySpecList *sort_sequence,
-                    int *sort_status);
+                    int *sort_status
+    ) GCC_ATTRIBUTE((warn_unused_result));    
 
 YAZ_EXPORT
 ZEBRA_RES zebra_select_databases(ZebraHandle zh, int num_bases, 
-                                const char **basenames);
+                                const char **basenames
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 YAZ_EXPORT
-ZEBRA_RES zebra_select_database(ZebraHandle zh, const char *basename);
+ZEBRA_RES zebra_select_database(ZebraHandle zh, const char *basename
+    ) GCC_ATTRIBUTE((warn_unused_result));
 
 YAZ_EXPORT
 void zebra_shadow_enable(ZebraHandle zh, int value);
@@ -485,7 +521,11 @@ YAZ_END_CDECL
  * \section intro_sec Introduction
  *
  * Zebra is a search engine for structure data, such as XML, MARC
- * and others. The following chapters briefly describe each of
+ * and others.
+ *
+ * API users should read the api.h for all the public definitions.
+ *
+ * The remaining sections briefly describe each of
  * Zebra major modules/components.
  *
  * \section util Base Utilities