add a read after the write

jcl/TXTWKR01.jcl

@@ -1,4 +1,4 @@
-//TXTWKR01 JOB (GCC),'File I/O Test',NOTIFY=@05054,CLASS=A,MSGCLASS=H,
+//TXTWKR01 JOB (GCC),'File I/O Test',NOTIFY=@05054,CLASS=A,MSGCLASS=A,
 //         MSGLEVEL=(1,1),REGION=4M,TIME=1440
 //STEP1   EXEC GCCCG,INFILE='@05054.SRCLIB.C(TXTWKR01)'
 //GO.TESTDD DD DSN=@05054.DATA(TESTMEM),DISP=SHR,

src/TXTWKR01.c

@@ -12,7 +12,7 @@ int main(void)
     int count = 0;
     char buf[LINE_LEN];
 
-    /* === Read phase === */
+    /* === Read phase before write === */
     fp = fopen("dd:TESTDD", "r");
     if (fp == NULL) {
         fputs("Cannot open for read\n", stdout);
@@ -42,6 +42,22 @@ int main(void)
 
     fclose(fp);
 
+    /* === Read phase after write === */
+    fp = fopen("dd:TESTDD", "r");
+    if (fp == NULL) {
+        fputs("Cannot open for read\n", stdout);
+        return 1;
+    }
+
+    fputs("Existing content:\n", stdout);
+    while (fgets(buf, LINE_LEN, fp) && count < MAX_LINES) {
+        fputs(buf, stdout);                   /* echo to JES */
+        strncpy(lines[count], buf, LINE_LEN-1);
+        lines[count][LINE_LEN-1] = '\0';
+        count++;
+    }
+    fclose(fp);
+
     fputs("Append complete (via rewrite).\n", stdout);
     return 0;
 }