load libs and dbd if not already done and check versions

require.c

+#include <symLib.h>
+#include <sysSymTbl.h>
+#include <stdio.h>
+#include <string.h>
+#include <shellLib.h>
+#include <usrLib.h>
+
+int dbLoadDatabase(char *filename, char *path, char *substitutions);
+
+int require(char* lib, char* version)
+{
+    char libname[256];
+    char dbdname[256];
+    char symbol[256];
+    char** path;
+    char* loaded;
+    SYM_TYPE type;
+    
+    if (symFindByName(sysSymTbl, "LIB", (char**)&path, &type) != OK)
+    {
+        static char* here = ".";
+        path = &here;
+    }
+    if (!lib)
+    {
+        printf("Usage: require \"<libname>\" [, \"<version>\"]\n");
+        printf("Loads <libname>Lib[-<version>] and dbd/<libname>[-<version>].dbd\n");
+        printf("Directory is LIB = %s\n", *path);
+        return ERROR;
+    }
+    sprintf(symbol, "_%sLibRelease", lib);
+    if (version)
+    {
+        sprintf(libname, "%s/%sLib-%s", *path, lib, version);
+        sprintf(dbdname, "%s/dbd/%s-%s.dbd", *path, lib, version);
+    }
+    else
+    {
+        sprintf(libname, "%s/%sLib", *path, lib);
+        sprintf(dbdname, "%s/dbd/%s.dbd", *path, lib);
+    }
+
+    if (symFindByName(sysSymTbl, symbol, &loaded, &type) != OK)
+    {
+        /* Load library and dbd file of requested version */
+        if (ld(0, 0, libname) == NULL)
+        {
+            printf ("%s not loaded\n", libname);
+            return ERROR;
+        }
+        printf("%s loaded\n", libname);
+        if (dbLoadDatabase(dbdname, NULL, NULL) != OK)
+        {
+            printf ("%s not loaded\n", dbdname);
+            return ERROR;
+        }
+        printf("%s loaded\n", dbdname);
+        return OK;
+    }
+    else
+    {
+        /* Library already loaded. Check Version. */
+        if (version && strcmp(loaded, version) != 0)
+        {
+            int lmajor, lminor, lpatch, lmatches;
+            int major, minor, patch, matches;
+            
+            lmatches = sscanf(loaded, "%d.%d.%d", &lmajor, &lminor, &lpatch);
+            matches = sscanf(version, "%d.%d.%d", &major, &minor, &patch);
+            if (matches == 0 || lmatches == 0 /* non-numerical version*/
+                || major != lmajor
+                || (matches >= 2 && minor != lminor)
+                || (matches > 2 && patch != lpatch))
+            {
+                printf("Conflict between requested %s\nand already loaded version %s\n",
+                    libname, loaded);
+                shellScriptAbort();
+                return ERROR;
+            }
+        }
+        /* Loaded version is ok */
+        printf("%sLib-%s already loaded\n", lib, loaded);
+        return OK;
+    }
+}