ioc/dbStatic: add typed_dset

src/ioc/dbStatic/devSup.h

@@ -21,6 +21,7 @@
 /* structures defined elsewhere */
 struct dbCommon;
 struct devSup;
+struct ioscan_head; /* aka IOSCANPVT */
 
 #ifdef __cplusplus
 extern "C" {
@@ -38,6 +39,73 @@ typedef struct dset {   /* device support entry table */
     /*other functions are record dependent*/
 } dset;
 
+/** Type safe alternative to 'struct dset'
+ *
+ * Recommended usage
+ @code
+ long my_drv_init_record(dbCommon *prec);
+ long my_drv_get_iointr_info(int deattach, dbCommon *prec, IOCSCANPVT* pscan);
+ long my_longin_read(longinRecord *prec);
+ typedef struct {
+    typed_dset common;
+    long (*read)(longinRecord *prec);
+ } my_longin_dset;
+ static const my_longin_dset devLiMyDrvName = {{
+      5, // 4 from typed_dset + 1 more
+      NULL,
+      NULL,
+      &my_drv_init_record,
+      &my_drv_get_iointr_info
+    },
+    &my_longin_read
+ };
+ epicsExportAddress(dset,  devLiMyDrvName);
+ @endcode
+ */
+typedef struct typed_dset {
+    /** Number of function pointers which follow.  Must be >=4 */
+    long number;
+    /** Called from dbior() */
+    long (*report)(int lvl);
+    /** Called twice during iocInit().
+     * First with phase=0 early, before init_record() and array field alloc.
+     * Again with phase=1 after init_record()
+     */
+    long (*init)(int phase);
+    /** Called once per record instance */
+    long (*init_record)(struct dbCommon *prec);
+    /** Called when SCAN="I/O Intr" on startup, or after SCAN is changed.
+     *
+     * Caller must assign third arguement (IOCSCANPVT*).  eg.
+     @code
+     struct mpvt {
+        IOSCANPVT drvlist;
+     };
+     ...
+        // init code calls
+        scanIoInit(&pvt->drvlist);
+     ...
+     long my_get_ioint_info(int deattach, struct dbCommon *prec, IOCSCANPVT* pscan) {
+        if(prec->dpvt)
+            *pscan = &((mypvt*)prec->dpvt)->drvlist;
+     @endcode
+     *
+     * When a particular record instance can/will only used a single scan list, then
+     * the 'detach' argument should be ignored.
+     *
+     * If this is not the case, then the following should be noted.
+     * get_ioint_info() called with deattach=0 to fetch the scan list to which this record will be added.
+     * Again with detach=1 to fetch the scan list from which this record will be removed.
+     * Calls will be balanced.
+     * A call with detach=0 will be matched by a call with detach=1.
+     *
+     * @note get_ioint_info() will be called during IOC shutdown if the del_record()
+     *       extended callback is provided.  (from 3.15.0.1)
+     */
+    long (*get_ioint_info)(int deattach, struct dbCommon *prec, struct ioscan_head** pscan);
+    /*other functions are record dependent*/
+} typed_dset;
+
 typedef struct dsxt {   /* device support extension table */
     long (*add_record)(struct dbCommon *precord);
     long (*del_record)(struct dbCommon *precord);