make this run at a reasonable speed - say a few hundred times faster

src/mmapcat.c

@@ -2,25 +2,30 @@
 
 #include<fcntl.h>
 #include <unistd.h>
-#include <stdlib.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <stdio.h>
 
 int main(int argc, char **argv)
 {
-	int fd;
-	char *ptr;
-	struct stat64 st;
+	int fd,n;
+	char *ptr, *ptr2;
+	struct stat st;
 
 	fd=open(argv[1],O_RDONLY);
 	if(fd<0) {
 		perror(argv[1]);
 		exit(1);
 	}
-	fstat64(fd, &st);
-	ptr = mmap64(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
-	while (*ptr != 0)
-		write(1, ptr++, 1);
+	fstat(fd,&st);
+	if(st.st_size%4096==0) {
+		fprintf(stderr,"bad file size!\n");
+		exit(1);
+	}
+
+	ptr2 = ptr = mmap(NULL,st.st_size,PROT_READ,MAP_PRIVATE,fd,0);
+	while (*ptr!=0) ptr++;
+	write(1,ptr2,ptr - ptr2);
 	exit(0);
 }
+