diff --git a/libc/errno.lisp b/libc/errno.lisp
index 0178116..c906472 100644
--- a/libc/errno.lisp
+++ b/libc/errno.lisp
@@ -1,39 +1,46 @@
 (in-package #:vacietis.libc.errno.h)
 (in-readtable vacietis:vacietis)
 
-(define   EPERM	   1  "Operation not permitted (POSIX.1)")
-(define   ENOENT   2  "No such file or directory (POSIX.1)")
-(define   ESRCH	   3  "No such process (POSIX.1)")
-(define   EINTR	   4  "Interrupted function call (POSIX.1)")
-(define   EIO  	   5  "Input/output error")
-(define   ENXIO	   6  "No such device or address (POSIX.1)")
-(define   E2BIG	   7  "Argument list too long (POSIX.1)")
-(define   ENOEXEC  8  "Exec format error (POSIX.1)")
-(define   EBADF	   9  "Bad file descriptor (POSIX.1)")
-(define   ECHILD   10 "No child processes (POSIX.1)")
-(define   EAGAIN   11 "Resource  temporarily unavailable (POSIX.1)")
-(define   ENOMEM   12 "Not enough space (POSIX.1)")
-(define   EACCES   13 "Permission denied (POSIX.1)")
-(define   EFAULT   14 "Bad address (POSIX.1)")
-(define   ENOTBLK  15 "Block device required")
-(define   EBUSY	   16 "Device or resource busy (POSIX.1)")
-(define   EEXIST   17 "File exists (POSIX.1)")
-(define   EXDEV	   18 "Improper link (POSIX.1)")
-(define   ENODEV   19 "No such device (POSIX.1)")
-(define   ENOTDIR  20 "Not a directory (POSIX.1)")
-(define   EISDIR   21 "Is a directory (POSIX.1)")
-(define   EINVAL   22 "Invalid argument (POSIX.1)")
-(define   ENFILE   23 "Too many open files in system (POSIX.1)")
-(define   EMFILE   24 "Too many open files (POSIX.1)")
-(define   ENOTTY   25 "Inappropriate I/O control operation (POSIX.1)")
-(define   ETXTBSY  26 "Text file busy (POSIX.1)")
-(define   EFBIG	   27 "File too large (POSIX.1)")
-(define   ENOSPC   28 "No space left on device (POSIX.1)")
-(define   ESPIPE   29 "Invalid seek (POSIX.1)")
-(define   EROFS	   30 "Read-only file system (POSIX.1)")
-(define   EMLINK   31 "Too many links (POSIX.1)")
-(define   EPIPE	   32 "Broken pipe (POSIX.1)")
-(define   EDOM 	   33 "Mathematics argument out of domain of function (POSIX.1, C99)")
-(define   ERANGE   34 "Result too large (POSIX.1, C99)")
+(defvar errno-strings (make-array 35))
+
+(defmacro deferr (name number msg)
+  `(progn
+     (setf (aref errno-strings ,number) (string-to-char* ,msg))
+     (define ,name ,number ,msg)))
+
+(deferr   EPERM	   1  "Operation not permitted (POSIX.1)")
+(deferr   ENOENT   2  "No such file or directory (POSIX.1)")
+(deferr   ESRCH	   3  "No such process (POSIX.1)")
+(deferr   EINTR	   4  "Interrupted function call (POSIX.1)")
+(deferr   EIO  	   5  "Input/output error")
+(deferr   ENXIO	   6  "No such device or address (POSIX.1)")
+(deferr   E2BIG	   7  "Argument list too long (POSIX.1)")
+(deferr   ENOEXEC  8  "Exec format error (POSIX.1)")
+(deferr   EBADF	   9  "Bad file descriptor (POSIX.1)")
+(deferr   ECHILD   10 "No child processes (POSIX.1)")
+(deferr   EAGAIN   11 "Resource  temporarily unavailable (POSIX.1)")
+(deferr   ENOMEM   12 "Not enough space (POSIX.1)")
+(deferr   EACCES   13 "Permission denied (POSIX.1)")
+(deferr   EFAULT   14 "Bad address (POSIX.1)")
+(deferr   ENOTBLK  15 "Block device required")
+(deferr   EBUSY	   16 "Device or resource busy (POSIX.1)")
+(deferr   EEXIST   17 "File exists (POSIX.1)")
+(deferr   EXDEV	   18 "Improper link (POSIX.1)")
+(deferr   ENODEV   19 "No such device (POSIX.1)")
+(deferr   ENOTDIR  20 "Not a directory (POSIX.1)")
+(deferr   EISDIR   21 "Is a directory (POSIX.1)")
+(deferr   EINVAL   22 "Invalid argument (POSIX.1)")
+(deferr   ENFILE   23 "Too many open files in system (POSIX.1)")
+(deferr   EMFILE   24 "Too many open files (POSIX.1)")
+(deferr   ENOTTY   25 "Inappropriate I/O control operation (POSIX.1)")
+(deferr   ETXTBSY  26 "Text file busy (POSIX.1)")
+(deferr   EFBIG	   27 "File too large (POSIX.1)")
+(deferr   ENOSPC   28 "No space left on device (POSIX.1)")
+(deferr   ESPIPE   29 "Invalid seek (POSIX.1)")
+(deferr   EROFS	   30 "Read-only file system (POSIX.1)")
+(deferr   EMLINK   31 "Too many links (POSIX.1)")
+(deferr   EPIPE	   32 "Broken pipe (POSIX.1)")
+(deferr   EDOM 	   33 "Mathematics argument out of domain of function (POSIX.1, C99)")
+(deferr   ERANGE   34 "Result too large (POSIX.1, C99)")
 
 (defvar errno 0)
diff --git a/libc/include/ctype.h b/libc/include/ctype.h
deleted file mode 100644
index e69de29..0000000
diff --git a/libc/include/math.h b/libc/include/math.h
deleted file mode 100644
index e69de29..0000000
diff --git a/libc/include/stdio.h b/libc/include/stdio.h
deleted file mode 100644
index fdb6e4b..0000000
--- a/libc/include/stdio.h
+++ /dev/null
@@ -1,19 +0,0 @@
-typedef T FILE;
-
-#define EOF -1
-
-/* these constants are important but here defined arbitrarily */
-#define FILENAME_MAX 1024
-#define FOPEN_MAX 99999
-#define BUFSIZ 512
-#define L_tmpnam 16
-#define TMP_MAX 99999
-#define _IOFBF 1
-#define _IOLBF 2
-#define _IONBF 3
-
-#define getchar()   getc(stdin)
-#define getc(f)     fgetc(f)
-#define putc(c, f)  fputc(c, f)
-#define putchar(c)  putc(c, stdout)
-#define setbuf(fd, buf) setvbuf(fd, buf, _IOFBF, BUFSIZ)
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
deleted file mode 100644
index 68a9742..0000000
--- a/libc/include/stdlib.h
+++ /dev/null
@@ -1,10 +0,0 @@
-/*
- * stdlib.h for ZETA-C: General Utilities
- */
-
-int atoi();
-long atol();
-char *malloc();
-void *calloc();
-void free();
-void abort(), exit();
diff --git a/libc/include/string.h b/libc/include/string.h
deleted file mode 100644
index f8c1ed1..0000000
--- a/libc/include/string.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
- STRING.H for ZETA-C: declarations for string processing functions.
- Note this file does not have a package specification, as it will be
- read into (potentially) many different packages.
-
- This is identical to ZETA-C:Include;STRINGS.H.  */
-
-extern char *strcat(), *strchr(), *strcpy(), *strncat(), *strncpy();
-extern char *strpbrk(), *strrchr(), *strrpbrk();
-extern int strcmp(), strlen(), strcspn(), strncmp(), strpos();
-extern int strrpos(), strspn();
-extern void *memcpy(), *memmove(), *memset(), *memchr();
-extern int memcmp();
-
-
-/* End of STRING.H */
diff --git a/libc/stdio.lisp b/libc/stdio.lisp
index 0fafe86..7cc5b5d 100644
--- a/libc/stdio.lisp
+++ b/libc/stdio.lisp
@@ -19,9 +19,6 @@
   (setf (feof fd)   0
         (ferror fd) 0))
 
-(defun perror (str)
-  (fprintf stderr "%s: %s\n" str "error message"))
-
 ;;; file operations
 
 ;; have to do something about EEXIST
@@ -97,10 +94,6 @@
        (progn (replace str newname :end1 (length newname))
               str))))
 
-(defun setvbuf (fd# buf mode size)
-  (declare (ignore fd# buf mode size))
-  0)
-
 ;;; character I/O
 
 (defun fgetc (fd)
@@ -112,6 +105,12 @@
       (setf (ferror fd) EIO)
       EOF)))
 
+(defun getc (fd)
+  (fgetc fd))
+
+(defun getchar ()
+  (getc stdin))
+
 (defun fputc (c fd)
   (handler-case (progn (write-char (code-char c) (fd-stream fd))
                        c)
@@ -119,6 +118,12 @@
       (setf (ferror fd) EIO)
       EOF)))
 
+(defun putc (c fd)
+  (fputc c fd))
+
+(defun putchar (c)
+  (fputc c stdout))
+
 (defun fgets-is-dumb (str n fd replace-newline?)
   (handler-case
       (let ((stream (fd-stream fd)))
@@ -251,3 +256,27 @@
 
 (defun snprintf (string max-length fmt &rest args))
 
+(defun perror (str)
+  (if (or (eql NULL str)
+          (eql 0 (aref (memptr-mem str) (memptr-ptr str))))
+      (fprintf stderr (string-to-char* "%s\\n") (strerror errno))
+      (fprintf stderr (string-to-char* "%s: %s\\n") str (strerror errno))))
+
+;;; things that have no effect
+
+(defun setvbuf (fd buf mode size)
+  (declare (ignore fd buf mode size))
+  0)
+
+(defun setbuf (fd buf)
+  (declare (ignore fd buf))
+  0)
+
+(define FILENAME_MAX 1024)
+(define FOPEN_MAX    1024)
+(define BUFSIZ       512)
+(define L_tmpnam     16)
+(define TMP_MAX      1024)
+(define _IOFBF       1)
+(define _IOLBF       2)
+(define _IONBF       3)
diff --git a/libc/stdlib.lisp b/libc/stdlib.lisp
index 4eac270..ed70286 100644
--- a/libc/stdlib.lisp
+++ b/libc/stdlib.lisp
@@ -108,8 +108,8 @@
 
 ;;; program environment
 
-(defconstant EXIT_SUCCESS 0)
-(defconstant EXIT_FAILURE 1)
+(define EXIT_SUCCESS 0)
+(define EXIT_FAILURE 1)
 
 (defun abort ()
   (throw 'vacietis::c-exit EXIT_FAILURE))
diff --git a/libc/string.c b/libc/string.c
index 8a94a98..8a428e1 100644
--- a/libc/string.c
+++ b/libc/string.c
@@ -3,86 +3,6 @@
 
 #define size_t int
 
-char *strcpy(char *s1, const char *s2) {
-  char *s = s1;
-  while ( (*s++ = *s2++) != 0 );
-  return s1;
-}
-
-char *strncpy(char *s1, const char *s2, size_t n) {
-	char *s = s1;
-
-	while (n) {
-		if ((*s = *s2) != 0) s2++; /* Need to fill tail with 0s. */
-		++s;
-		--n;
-	}
-
-	return s1;
-}
-
-char *strcat(char *  s1,  const char *  s2)
-{
-	 char *s = s1;
-
-	while (*s++);
-	--s;
-	while ((*s++ = *s2++) != 0);
-
-	return s1;
-}
-
-char *strncat(char *  s1,  const char *  s2,
-				size_t n)
-{
-	 char *s = s1;
-
-	while (*s++);
-	--s;
-	while (n && ((*s = *s2++) != 0)) {
-		--n;
-		++s;
-	}
-	*s = 0;
-
-	return s1;
-}
-
-int strcmp( const char *s1,  const char *s2)
-{
-
-	int r;
-
-	while (((r = ((int)(*((uchar *)s1))) - *((uchar *)s2++))
-			== 0) && *s1++);
-
-	return r;
-}
-
-// yup, this is real code, formatting and all
-int strncmp( const char *s1,  const char *s2, size_t n)
-{
-	int r = 0;
-
-	while (n--
-		   && ((r = ((int)(*((unsigned char *)s1))) - *((unsigned char *)s2++))
-			== 0)
-		   && *s1++);
-
-	return r;
-}
-
-char *strchr( const char *s, int c)
-{
-	do {
-		if (*s == ((char)c)) {
-			return (char *) s;	/* silence the warning */
-		}
-	} while (*s++);
-
-	return NULL;
-}
-
 char *strrchr( const  char *s, int c)
 {
 	 const char *p;
@@ -146,12 +66,6 @@ char *strstr(const char *s1, const char *s2)
 	} while (1);
 }
 
-size_t strlen(const char *s) {
-	const char *p;
-	for (p=s ; *p ; p++);
-	return p - s;
-}
-
 char *strtok(char *  s1, const char *  s2) {
 	static char *next_start;	/* Initialized to 0 since in bss. */
 	return strtok_r(s1, s2, &next_start);
@@ -173,3 +87,123 @@ char *strtok_r(char *  s1, const char *  s2, char **  next_start) {
   }
   return s;
 }
+
+// The following functions are from ZetaC
+
+// str functions
+
+char *strcpy (char *s1, char *s2) {
+  char *s1temp = s1;
+
+  do *s1++ = *s2; while (*s2++);
+  return s1temp;
+}
+
+char *strncpy (char *s1, char *s2, int n) {
+  char *s1temp = s1;
+
+  while (--n >= 0) *s1++ = *s2 ? *s2++ : NULL;
+  return s1temp;
+}
+
+char *strcat (char *s1, char *s2) {
+  strcpy (s1 + strlen (s1), s2);
+  return s1;
+}
+
+char *strncat (char *s1, char *s2, int n) {
+  char *s1tmp;
+
+  s1tmp = s1 + strlen (s1);	/* Remember where the original string ended */
+  strncpy (s1tmp, s2, n);       /* The real work happens here */
+  s1tmp[n] = NUL;	        /* Must guarantee that result ends in NUL */
+  return s1;
+}
+
+char *strchr (char *s, char *c) {
+  do if (*s == c) return s; while (*s++);
+  return NULL;
+}
+
+
+int strcmp (char *s1, char *s2) {
+  char c1, c2;
+
+  while (*s1 || *s2) {
+    c1 = *s1++;
+    c2 = *s2++;
+    if (c1 < c2) return -1;
+    if (c1 > c2) return 1;
+  }
+  return 0;
+}
+
+int strncmp (char *s1, char *s2, int n) {
+  char c1, c2;
+
+  while (n-- > 0 && (*s1 || *s2)) {	 /* Just like strcmp, but for < n chars */
+    c1 = *s1++;
+    c2 = *s2++;
+    if (c1 < c2) return -1;
+    if (c1 > c2) return 1;
+  }
+  return 0;
+}
+
+int strlen (char *s) {
+  char *s0 = s;
+
+  while (*s) s++;
+  return s - s0;
+}
+
+int strcspn (char *s1, char *s2) {
+  int n = 0;
+
+  while (s1[n] &&              /* WHILE not at the end of S1, and */
+         !strchr(s2, s1[n]))   /* not not at one of S2s chars */
+    n++;
+  return n;
+}
+
+// mem functions
+
+char *memcpy (char *dest, char *src, int nbytes) {
+  void *tdest = dest;
+  while (nbytes-- > 0) *dest++ = *src++;
+  return tdest;
+}
+
+char *memmove (char *dest, char *src, int nbytes) {
+  void *tdest = destv;
+
+  if (src > dest) while (nbytes-- > 0) *dest++ = *src++;
+  else {
+    src += nbytes;
+    dest += nbytes;
+    while (nbytes-- > 0) *--dest = *--src;
+  }
+  return tdest;
+}
+
+char *memset (char *dest, char c, int nbytes) {
+  while (nbytes-- > 0) *dest++ = c;
+  return destv;
+}
+
+void *memchr (char *sv, char c, int nbytes) {
+  while (nbytes-- > 0) if (*s++ == c) return (void *)(s - 1);
+  return (void *)NULL;
+}
+
+int memcmp (char *m1v, char *m2v, int nbytes) {
+  char c1, c2;
+
+  while (nbytes-- > 0) {
+    c1 = *m1++;
+    c2 = *m2++;
+    if (c1 < c2) return -1;
+    if (c1 > c2) return 1;
+  }
+  return 0;
+}
diff --git a/libc/string.lisp b/libc/string.lisp
index 03c02e7..c59e8bf 100644
--- a/libc/string.lisp
+++ b/libc/string.lisp
@@ -2,4 +2,4 @@
 (in-readtable vacietis)
 
 (defun strerror (errnum)
-  (string-to-char* "Some kind of error"))
+  (aref vacietis.libc.errno.h::errno-strings errnum))