docs: Update libpq and testlo examples

Josh Kupershmidt

Author: bmomjian

doc/src/sgml/libpq.sgml

@@ -7906,12 +7906,17 @@ main(int argc, char **argv)
  *
  *   INSERT INTO TBL1 VALUES (10);
  */
+
+#ifdef WIN32
+#include <windows.h>
+#endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <sys/time.h>
-#include <libpq-fe.h>
+#include <sys/types.h>
+#include "libpq-fe.h"
 
 static void
 exit_nicely(PGconn *conn)
@@ -8045,11 +8050,17 @@ main(int argc, char **argv)
  *  t = (8 bytes) 'ho there'
  *  b = (5 bytes) \004\003\002\001\000
  */
+
+#ifdef WIN32
+#include <windows.h>
+#endif
+
 #include <stdio.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <string.h>
 #include <sys/types.h>
-#include <libpq-fe.h>
+#include "libpq-fe.h"
 
 /* for ntohl/htonl */
 #include <netinet/in.h>
@@ -8160,10 +8171,10 @@ main(int argc, char **argv)
      * out-of-line parameters, as well as binary transmission of data.
      *
      * This first example transmits the parameters as text, but receives the
-     * results in binary format.  By using out-of-line parameters we can
-     * avoid a lot of tedious mucking about with quoting and escaping, even
-     * though the data is text.  Notice how we don't have to do anything
-     * special with the quote mark in the parameter value.
+     * results in binary format.  By using out-of-line parameters we can avoid
+     * a lot of tedious mucking about with quoting and escaping, even though
+     * the data is text.  Notice how we don't have to do anything special with
+     * the quote mark in the parameter value.
      */
 
     /* Here is our out-of-line parameter value */
@@ -8190,8 +8201,8 @@ main(int argc, char **argv)
     PQclear(res);
 
     /*
-     * In this second example we transmit an integer parameter in binary
-     * form, and again retrieve the results in binary form.
+     * In this second example we transmit an integer parameter in binary form,
+     * and again retrieve the results in binary form.
      *
      * Although we tell PQexecParams we are letting the backend deduce
      * parameter type, we really force the decision by casting the parameter

doc/src/sgml/lobj.sgml

@@ -597,27 +597,39 @@ SELECT lo_export(image.raster, '/tmp/motd') FROM image
   <example id="lo-example">
    <title>Large Objects with <application>libpq</application> Example Program</title>
 <programlisting><![CDATA[
-/*--------------------------------------------------------------
+/*-------------------------------------------------------------------------
  *
- * testlo.c--
+ * testlo.c
  *    test using large objects with libpq
  *
- * Copyright (c) 1994, Regents of the University of California
+ * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
  *
- *--------------------------------------------------------------
+ *
+ * IDENTIFICATION
+ *    src/test/examples/testlo.c
+ *
+ *-------------------------------------------------------------------------
  */
 #include <stdio.h>
+#include <stdlib.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+
 #include "libpq-fe.h"
 #include "libpq/libpq-fs.h"
 
-#define BUFSIZE          1024
+#define BUFSIZE         1024
 
 /*
- * importFile
+ * importFile -
  *    import file "in_filename" into database as large object "lobjOid"
  *
  */
-Oid
+static Oid
 importFile(PGconn *conn, char *filename)
 {
     Oid         lobjId;
@@ -633,15 +645,15 @@ importFile(PGconn *conn, char *filename)
     fd = open(filename, O_RDONLY, 0666);
     if (fd < 0)
     {                           /* error */
-        fprintf(stderr, "cannot open unix file %s\n", filename);
+        fprintf(stderr, "cannot open unix file\"%s\"\n", filename);
     }
 
     /*
      * create the large object
      */
     lobjId = lo_creat(conn, INV_READ | INV_WRITE);
     if (lobjId == 0)
-        fprintf(stderr, "cannot create large object\n");
+        fprintf(stderr, "cannot create large object");
 
     lobj_fd = lo_open(conn, lobjId, INV_WRITE);
 
@@ -652,16 +664,16 @@ importFile(PGconn *conn, char *filename)
     {
         tmp = lo_write(conn, lobj_fd, buf, nbytes);
         if (tmp < nbytes)
-            fprintf(stderr, "error while reading large object\n");
+            fprintf(stderr, "error while reading \"%s\"", filename);
     }
 
-    (void) close(fd);
-    (void) lo_close(conn, lobj_fd);
+    close(fd);
+    lo_close(conn, lobj_fd);
 
     return lobjId;
 }
 
-void
+static void
 pickout(PGconn *conn, Oid lobjId, int start, int len)
 {
     int         lobj_fd;
@@ -671,10 +683,7 @@ pickout(PGconn *conn, Oid lobjId, int start, int len)
 
     lobj_fd = lo_open(conn, lobjId, INV_READ);
     if (lobj_fd < 0)
-    {
-        fprintf(stderr, "cannot open large object %d\n",
-                lobjId);
-    }
+        fprintf(stderr, "cannot open large object %u", lobjId);
 
     lo_lseek(conn, lobj_fd, start, SEEK_SET);
     buf = malloc(len + 1);
@@ -683,16 +692,18 @@ pickout(PGconn *conn, Oid lobjId, int start, int len)
     while (len - nread > 0)
     {
         nbytes = lo_read(conn, lobj_fd, buf, len - nread);
-        buf[nbytes] = ' ';
+        buf[nbytes] = '\0';
         fprintf(stderr, ">>> %s", buf);
         nread += nbytes;
+        if (nbytes <= 0)
+            break;              /* no more data? */
     }
     free(buf);
     fprintf(stderr, "\n");
     lo_close(conn, lobj_fd);
 }
 
-void
+static void
 overwrite(PGconn *conn, Oid lobjId, int start, int len)
 {
     int         lobj_fd;
@@ -703,35 +714,38 @@ overwrite(PGconn *conn, Oid lobjId, int start, int len)
 
     lobj_fd = lo_open(conn, lobjId, INV_WRITE);
     if (lobj_fd < 0)
-    {
-        fprintf(stderr, "cannot open large object %d\n",
-                lobjId);
-    }
+        fprintf(stderr, "cannot open large object %u", lobjId);
 
     lo_lseek(conn, lobj_fd, start, SEEK_SET);
     buf = malloc(len + 1);
 
     for (i = 0; i < len; i++)
         buf[i] = 'X';
-    buf[i] = ' ';
+    buf[i] = '\0';
 
     nwritten = 0;
     while (len - nwritten > 0)
     {
         nbytes = lo_write(conn, lobj_fd, buf + nwritten, len - nwritten);
         nwritten += nbytes;
+        if (nbytes <= 0)
+        {
+            fprintf(stderr, "\nWRITE FAILED!\n");
+            break;
+        }
     }
     free(buf);
     fprintf(stderr, "\n");
     lo_close(conn, lobj_fd);
 }
 
+
 /*
- * exportFile
+ * exportFile -
  *    export large object "lobjOid" to file "out_filename"
  *
  */
-void
+static void
 exportFile(PGconn *conn, Oid lobjId, char *filename)
 {
     int         lobj_fd;
@@ -745,18 +759,15 @@ exportFile(PGconn *conn, Oid lobjId, char *filename)
      */
     lobj_fd = lo_open(conn, lobjId, INV_READ);
     if (lobj_fd < 0)
-    {
-        fprintf(stderr, "cannot open large object %d\n",
-                lobjId);
-    }
+        fprintf(stderr, "cannot open large object %u", lobjId);
 
     /*
      * open the file to be written to
      */
-    fd = open(filename, O_CREAT | O_WRONLY, 0666);
+    fd = open(filename, O_CREAT | O_WRONLY | O_TRUNC, 0666);
     if (fd < 0)
     {                           /* error */
-        fprintf(stderr, "cannot open unix file %s\n",
+        fprintf(stderr, "cannot open unix file\"%s\"",
                 filename);
     }
 
@@ -768,18 +779,18 @@ exportFile(PGconn *conn, Oid lobjId, char *filename)
         tmp = write(fd, buf, nbytes);
         if (tmp < nbytes)
         {
-            fprintf(stderr, "error while writing %s\n",
+            fprintf(stderr, "error while writing \"%s\"",
                     filename);
         }
     }
 
-    (void) lo_close(conn, lobj_fd);
-    (void) close(fd);
+    lo_close(conn, lobj_fd);
+    close(fd);
 
     return;
 }
 
-void
+static void
 exit_nicely(PGconn *conn)
 {
     PQfinish(conn);
@@ -813,37 +824,40 @@ main(int argc, char **argv)
     conn = PQsetdb(NULL, NULL, NULL, NULL, database);
 
     /* check to see that the backend connection was successfully made */
-    if (PQstatus(conn) == CONNECTION_BAD)
+    if (PQstatus(conn) != CONNECTION_OK)
     {
-        fprintf(stderr, "Connection to database '%s' failed.\n", database);
-        fprintf(stderr, "%s", PQerrorMessage(conn));
+        fprintf(stderr, "Connection to database failed: %s",
+                PQerrorMessage(conn));
         exit_nicely(conn);
     }
 
     res = PQexec(conn, "begin");
     PQclear(res);
-
-    printf("importing file %s\n", in_filename);
+    printf("importing file \"%s\" ...\n", in_filename);
 /*  lobjOid = importFile(conn, in_filename); */
     lobjOid = lo_import(conn, in_filename);
-/*
-    printf("as large object %d.\n", lobjOid);
+    if (lobjOid == 0)
+        fprintf(stderr, "%s\n", PQerrorMessage(conn));
+    else
+    {
+        printf("\tas large object %u.\n", lobjOid);
 
-    printf("picking out bytes 1000-2000 of the large object\n");
-    pickout(conn, lobjOid, 1000, 1000);
+        printf("picking out bytes 1000-2000 of the large object\n");
+        pickout(conn, lobjOid, 1000, 1000);
 
-    printf("overwriting bytes 1000-2000 of the large object with X's\n");
-    overwrite(conn, lobjOid, 1000, 1000);
-*/
+        printf("overwriting bytes 1000-2000 of the large object with X's\n");
+        overwrite(conn, lobjOid, 1000, 1000);
 
-    printf("exporting large object to file %s\n", out_filename);
-/*    exportFile(conn, lobjOid, out_filename); */
-    lo_export(conn, lobjOid, out_filename);
+        printf("exporting large object to file \"%s\" ...\n", out_filename);
+/*      exportFile(conn, lobjOid, out_filename); */
+        if (lo_export(conn, lobjOid, out_filename) < 0)
+            fprintf(stderr, "%s\n", PQerrorMessage(conn));
+    }
 
     res = PQexec(conn, "end");
     PQclear(res);
     PQfinish(conn);
-    exit(0);
+    return 0;
 }
 ]]>
 </programlisting>