syserror() improvement and some usage in the coreutils

src/cat.c

@@ -2,6 +2,8 @@
 #include <unistd.h>
 #include <fcntl.h>
 
+#include "lib/error.h"
+
 int
 cat(int fd, char *string)
 {
@@ -11,15 +13,10 @@ cat(int fd, char *string)
   while((lines=read(fd, buf, (long)sizeof(buf)))>0)
     {
       if(write(1,buf,lines)!=lines)
-        {
-	  fprintf(stderr,"Error copying. %s",string);
-	  return 1;
-        }
+	syserror("Error copying string %s\n",string);
+      
       if (lines < 0)
-	{
-	  fprintf(stderr,"Error reading %s",string);
-	  return 1;
-	}
+	syserror("Error reading %s\n",string);
     }
   return 0;
 }
@@ -37,7 +34,7 @@ main(int argc, char *argv[])
 	 {
 	   fd = open(argv[i],O_RDONLY);
 	   if(fd<0)
-	     fprintf(stderr,"Cannot open %s\n",argv[i]);
+	     syserror("Cannot open %s\n",argv[i]);
 	   else
 	     {
 	       cat(fd,argv[i]);

src/lib/error.c

@@ -1,8 +1,12 @@
 #include <stdio.h>
+#include <stdarg.h>
 #include "error.h"
 
-int syserror(char *msg)
+int syserror(const char *msg, ...)
 {
-  fprintf(stderr,"%s",msg);
+  va_list args;
+  va_start(args,msg);
+  vfprintf(stderr,msg,args);
+  va_end(args);
   return 1;
 }

src/lib/error.h

@@ -1 +1,3 @@
-int syserror(char *msg);
+#include <stdio.h>
+
+int syserror(const char *msg, ...);

src/rm.c

@@ -1,5 +1,7 @@
 #include <stdio.h>
 
+#include "lib/error.h"
+
 int
 main(int argc, char *argv[])
 {
@@ -14,7 +16,7 @@ main(int argc, char *argv[])
       int fd = remove(argv[i]);
       if(fd == -1)
         {
-          fprintf(stderr,"Error removing file: %s\n",argv[i]);
+          syserror("Error removing file: %s\n",argv[i]);
 
         }
     }