revise C for JCC compatibility

jcl/TXTWKR01.jcl

@@ -2,4 +2,4 @@
 //         NOTIFY=@05054,CLASS=A,MSGCLASS=H,
 //         MSGLEVEL=(1,1),REGION=4M,TIME=1440
 //STEP1   EXEC JCCCLG,INFILE='@05054.SRCLIB.C(TXTWKR01)'
-//GO.TESTDD DD DSN=@05054.DATA(TESTMEM),DISP=SHR
+//GO.TESTDD DD DSN=@05054.DATA(TESTMEM),DISP=SHR

src/TXTWKR01.c

@@ -1,49 +1,22 @@
 #include <stdio.h>
-#include <errno.h>
-
-#define BUFFER_SIZE 256
-
-/* Simple program to read and append to a single PDS member via DD name. */
-/* Author: Greg Gauthier */
-/* Date: 2026-02-08 */
-/* NOTE: No single-line comments due to MVS SYSIN/JCL interpretation. */
 
 int main()
 {
-    FILE *fp_read;
-    FILE *fp_append;
-    char buffer[BUFFER_SIZE];
+    FILE *fp;
+    char buf[256];
 
-    /* First: open for reading only to dump current content */
-    fp_read = fopen("dd:TESTDD", "r");
-    if (fp_read == NULL)
-    {
-        perror("fopen read failed");
-        printf("errno = %d\n", __errno());
+    fp = fopen("dd:TESTDD", "r");
+    if (fp == NULL) {
+        printf((char *)"fopen read failed\n");
         return 1;
     }
 
-    printf("Existing content:\n");
-    while (fgets(buffer, BUFFER_SIZE, fp_read) != NULL)
-    {
-        printf("%s", buffer);
+    printf((char *)"Existing content:\n");
+    while (fgets(buf, 256, fp) != NULL) {
+        printf((char *)"%s", buf);
     }
-    fclose(fp_read);
-
-    /* Second: open for append only to add the new line */
-    fp_append = fopen("dd:TESTDD", "a");
-    if (fp_append == NULL)
-    {
-        perror("fopen append failed");
-        printf("errno = %d\n", __errno());
-        return 1;
-    }
-
-    fprintf(fp_append, "Appended from C program!\n");
-    fclose(fp_append);
-
-    printf("Append complete.\n");
+    fclose(fp);
 
+    printf((char *)"Read complete.\n");
     return 0;
-}
-
+}