Commits

king  committed 0a9027c

Importing gcc 3.3.2.

  • Participants
  • Parent commits cdc83df
  • Branches GCC

Comments (0)

Files changed (1)

File GCC/libiberty/strerror.c

+/* Extended support for using errno values.
+   Written by Fred Fish.  fnf@cygnus.com
+   This file is in the public domain.  --Per Bothner.  */
+
+#include "ansidecl.h"
+#include "libiberty.h"
+
+#include "config.h"
+
+#ifdef HAVE_SYS_ERRLIST
+/* Note that errno.h (not sure what OS) or stdio.h (BSD 4.4, at least)
+   might declare sys_errlist in a way that the compiler might consider
+   incompatible with our later declaration, perhaps by using const
+   attributes.  So we hide the declaration in errno.h (if any) using a
+   macro. */
+#define sys_nerr sys_nerr__
+#define sys_errlist sys_errlist__
+#endif
+
+#include <stdio.h>
+#include <errno.h>
+
+#ifdef HAVE_SYS_ERRLIST
+#undef sys_nerr
+#undef sys_errlist
+#endif
+
+/*  Routines imported from standard C runtime libraries. */
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#else
+extern PTR malloc ();
+#endif
+
+#ifdef HAVE_STRING_H
+#include <string.h>
+#else
+extern PTR memset ();
+#endif
+
+#ifndef MAX
+#  define MAX(a,b) ((a) > (b) ? (a) : (b))
+#endif
+
+static void init_error_tables PARAMS ((void));
+
+/* Translation table for errno values.  See intro(2) in most UNIX systems
+   Programmers Reference Manuals.
+
+   Note that this table is generally only accessed when it is used at runtime
+   to initialize errno name and message tables that are indexed by errno
+   value.
+
+   Not all of these errnos will exist on all systems.  This table is the only
+   thing that should have to be updated as new error numbers are introduced.
+   It's sort of ugly, but at least its portable. */
+
+struct error_info
+{
+  const int value;		/* The numeric value from <errno.h> */
+  const char *const name;	/* The equivalent symbolic value */
+#ifndef HAVE_SYS_ERRLIST
+  const char *const msg;	/* Short message about this value */
+#endif
+};
+
+#ifndef HAVE_SYS_ERRLIST
+#   define ENTRY(value, name, msg)	{value, name, msg}
+#else
+#   define ENTRY(value, name, msg)	{value, name}
+#endif
+
+static const struct error_info error_table[] =
+{
+#if defined (EPERM)
+  ENTRY(EPERM, "EPERM", "Not owner"),
+#endif
+#if defined (ENOENT)
+  ENTRY(ENOENT, "ENOENT", "No such file or directory"),
+#endif
+#if defined (ESRCH)
+  ENTRY(ESRCH, "ESRCH", "No such process"),
+#endif
+#if defined (EINTR)
+  ENTRY(EINTR, "EINTR", "Interrupted system call"),
+#endif
+#if defined (EIO)
+  ENTRY(EIO, "EIO", "I/O error"),
+#endif
+#if defined (ENXIO)
+  ENTRY(ENXIO, "ENXIO", "No such device or address"),
+#endif
+#if defined (E2BIG)
+  ENTRY(E2BIG, "E2BIG", "Arg list too long"),
+#endif
+#if defined (ENOEXEC)
+  ENTRY(ENOEXEC, "ENOEXEC", "Exec format error"),
+#endif
+#if defined (EBADF)
+  ENTRY(EBADF, "EBADF", "Bad file number"),
+#endif
+#if defined (ECHILD)
+  ENTRY(ECHILD, "ECHILD", "No child processes"),
+#endif
+#if defined (EWOULDBLOCK)	/* Put before EAGAIN, sometimes aliased */
+  ENTRY(EWOULDBLOCK, "EWOULDBLOCK", "Operation would block"),
+#endif
+#if defined (EAGAIN)
+  ENTRY(EAGAIN, "EAGAIN", "No more processes"),
+#endif
+#if defined (ENOMEM)
+  ENTRY(ENOMEM, "ENOMEM", "Not enough space"),
+#endif
+#if defined (EACCES)
+  ENTRY(EACCES, "EACCES", "Permission denied"),
+#endif
+#if defined (EFAULT)
+  ENTRY(EFAULT, "EFAULT", "Bad address"),
+#endif
+#if defined (ENOTBLK)
+  ENTRY(ENOTBLK, "ENOTBLK", "Block device required"),
+#endif
+#if defined (EBUSY)
+  ENTRY(EBUSY, "EBUSY", "Device busy"),
+#endif
+#if defined (EEXIST)
+  ENTRY(EEXIST, "EEXIST", "File exists"),
+#endif
+#if defined (EXDEV)
+  ENTRY(EXDEV, "EXDEV", "Cross-device link"),
+#endif
+#if defined (ENODEV)
+  ENTRY(ENODEV, "ENODEV", "No such device"),
+#endif
+#if defined (ENOTDIR)
+  ENTRY(ENOTDIR, "ENOTDIR", "Not a directory"),
+#endif
+#if defined (EISDIR)
+  ENTRY(EISDIR, "EISDIR", "Is a directory"),
+#endif
+#if defined (EINVAL)
+  ENTRY(EINVAL, "EINVAL", "Invalid argument"),
+#endif
+#if defined (ENFILE)
+  ENTRY(ENFILE, "ENFILE", "File table overflow"),
+#endif
+#if defined (EMFILE)
+  ENTRY(EMFILE, "EMFILE", "Too many open files"),
+#endif
+#if defined (ENOTTY)
+  ENTRY(ENOTTY, "ENOTTY", "Not a typewriter"),
+#endif
+#if defined (ETXTBSY)
+  ENTRY(ETXTBSY, "ETXTBSY", "Text file busy"),
+#endif
+#if defined (EFBIG)
+  ENTRY(EFBIG, "EFBIG", "File too large"),
+#endif
+#if defined (ENOSPC)
+  ENTRY(ENOSPC, "ENOSPC", "No space left on device"),
+#endif
+#if defined (ESPIPE)
+  ENTRY(ESPIPE, "ESPIPE", "Illegal seek"),
+#endif
+#if defined (EROFS)
+  ENTRY(EROFS, "EROFS", "Read-only file system"),
+#endif
+#if defined (EMLINK)
+  ENTRY(EMLINK, "EMLINK", "Too many links"),
+#endif
+#if defined (EPIPE)
+  ENTRY(EPIPE, "EPIPE", "Broken pipe"),
+#endif
+#if defined (EDOM)
+  ENTRY(EDOM, "EDOM", "Math argument out of domain of func"),
+#endif
+#if defined (ERANGE)
+  ENTRY(ERANGE, "ERANGE", "Math result not representable"),
+#endif
+#if defined (ENOMSG)
+  ENTRY(ENOMSG, "ENOMSG", "No message of desired type"),
+#endif
+#if defined (EIDRM)
+  ENTRY(EIDRM, "EIDRM", "Identifier removed"),
+#endif
+#if defined (ECHRNG)
+  ENTRY(ECHRNG, "ECHRNG", "Channel number out of range"),
+#endif
+#if defined (EL2NSYNC)
+  ENTRY(EL2NSYNC, "EL2NSYNC", "Level 2 not synchronized"),
+#endif
+#if defined (EL3HLT)
+  ENTRY(EL3HLT, "EL3HLT", "Level 3 halted"),
+#endif
+#if defined (EL3RST)
+  ENTRY(EL3RST, "EL3RST", "Level 3 reset"),
+#endif
+#if defined (ELNRNG)
+  ENTRY(ELNRNG, "ELNRNG", "Link number out of range"),
+#endif
+#if defined (EUNATCH)
+  ENTRY(EUNATCH, "EUNATCH", "Protocol driver not attached"),
+#endif
+#if defined (ENOCSI)
+  ENTRY(ENOCSI, "ENOCSI", "No CSI structure available"),
+#endif
+#if defined (EL2HLT)
+  ENTRY(EL2HLT, "EL2HLT", "Level 2 halted"),
+#endif
+#if defined (EDEADLK)
+  ENTRY(EDEADLK, "EDEADLK", "Deadlock condition"),
+#endif
+#if defined (ENOLCK)
+  ENTRY(ENOLCK, "ENOLCK", "No record locks available"),
+#endif
+#if defined (EBADE)
+  ENTRY(EBADE, "EBADE", "Invalid exchange"),
+#endif
+#if defined (EBADR)
+  ENTRY(EBADR, "EBADR", "Invalid request descriptor"),
+#endif
+#if defined (EXFULL)
+  ENTRY(EXFULL, "EXFULL", "Exchange full"),
+#endif
+#if defined (ENOANO)
+  ENTRY(ENOANO, "ENOANO", "No anode"),
+#endif
+#if defined (EBADRQC)
+  ENTRY(EBADRQC, "EBADRQC", "Invalid request code"),
+#endif
+#if defined (EBADSLT)
+  ENTRY(EBADSLT, "EBADSLT", "Invalid slot"),
+#endif
+#if defined (EDEADLOCK)
+  ENTRY(EDEADLOCK, "EDEADLOCK", "File locking deadlock error"),
+#endif
+#if defined (EBFONT)
+  ENTRY(EBFONT, "EBFONT", "Bad font file format"),
+#endif
+#if defined (ENOSTR)
+  ENTRY(ENOSTR, "ENOSTR", "Device not a stream"),
+#endif
+#if defined (ENODATA)
+  ENTRY(ENODATA, "ENODATA", "No data available"),
+#endif
+#if defined (ETIME)
+  ENTRY(ETIME, "ETIME", "Timer expired"),
+#endif
+#if defined (ENOSR)
+  ENTRY(ENOSR, "ENOSR", "Out of streams resources"),
+#endif
+#if defined (ENONET)
+  ENTRY(ENONET, "ENONET", "Machine is not on the network"),
+#endif
+#if defined (ENOPKG)
+  ENTRY(ENOPKG, "ENOPKG", "Package not installed"),
+#endif
+#if defined (EREMOTE)
+  ENTRY(EREMOTE, "EREMOTE", "Object is remote"),
+#endif
+#if defined (ENOLINK)
+  ENTRY(ENOLINK, "ENOLINK", "Link has been severed"),
+#endif
+#if defined (EADV)
+  ENTRY(EADV, "EADV", "Advertise error"),
+#endif
+#if defined (ESRMNT)
+  ENTRY(ESRMNT, "ESRMNT", "Srmount error"),
+#endif
+#if defined (ECOMM)
+  ENTRY(ECOMM, "ECOMM", "Communication error on send"),
+#endif
+#if defined (EPROTO)
+  ENTRY(EPROTO, "EPROTO", "Protocol error"),
+#endif
+#if defined (EMULTIHOP)
+  ENTRY(EMULTIHOP, "EMULTIHOP", "Multihop attempted"),
+#endif
+#if defined (EDOTDOT)
+  ENTRY(EDOTDOT, "EDOTDOT", "RFS specific error"),
+#endif
+#if defined (EBADMSG)
+  ENTRY(EBADMSG, "EBADMSG", "Not a data message"),
+#endif
+#if defined (ENAMETOOLONG)
+  ENTRY(ENAMETOOLONG, "ENAMETOOLONG", "File name too long"),
+#endif
+#if defined (EOVERFLOW)
+  ENTRY(EOVERFLOW, "EOVERFLOW", "Value too large for defined data type"),
+#endif
+#if defined (ENOTUNIQ)
+  ENTRY(ENOTUNIQ, "ENOTUNIQ", "Name not unique on network"),
+#endif
+#if defined (EBADFD)
+  ENTRY(EBADFD, "EBADFD", "File descriptor in bad state"),
+#endif
+#if defined (EREMCHG)
+  ENTRY(EREMCHG, "EREMCHG", "Remote address changed"),
+#endif
+#if defined (ELIBACC)
+  ENTRY(ELIBACC, "ELIBACC", "Can not access a needed shared library"),
+#endif
+#if defined (ELIBBAD)
+  ENTRY(ELIBBAD, "ELIBBAD", "Accessing a corrupted shared library"),
+#endif
+#if defined (ELIBSCN)
+  ENTRY(ELIBSCN, "ELIBSCN", ".lib section in a.out corrupted"),
+#endif
+#if defined (ELIBMAX)
+  ENTRY(ELIBMAX, "ELIBMAX", "Attempting to link in too many shared libraries"),
+#endif
+#if defined (ELIBEXEC)
+  ENTRY(ELIBEXEC, "ELIBEXEC", "Cannot exec a shared library directly"),
+#endif
+#if defined (EILSEQ)
+  ENTRY(EILSEQ, "EILSEQ", "Illegal byte sequence"),
+#endif
+#if defined (ENOSYS)
+  ENTRY(ENOSYS, "ENOSYS", "Operation not applicable"),
+#endif
+#if defined (ELOOP)
+  ENTRY(ELOOP, "ELOOP", "Too many symbolic links encountered"),
+#endif
+#if defined (ERESTART)
+  ENTRY(ERESTART, "ERESTART", "Interrupted system call should be restarted"),
+#endif
+#if defined (ESTRPIPE)
+  ENTRY(ESTRPIPE, "ESTRPIPE", "Streams pipe error"),
+#endif
+#if defined (ENOTEMPTY)
+  ENTRY(ENOTEMPTY, "ENOTEMPTY", "Directory not empty"),
+#endif
+#if defined (EUSERS)
+  ENTRY(EUSERS, "EUSERS", "Too many users"),
+#endif
+#if defined (ENOTSOCK)
+  ENTRY(ENOTSOCK, "ENOTSOCK", "Socket operation on non-socket"),
+#endif
+#if defined (EDESTADDRREQ)
+  ENTRY(EDESTADDRREQ, "EDESTADDRREQ", "Destination address required"),
+#endif
+#if defined (EMSGSIZE)
+  ENTRY(EMSGSIZE, "EMSGSIZE", "Message too long"),
+#endif
+#if defined (EPROTOTYPE)
+  ENTRY(EPROTOTYPE, "EPROTOTYPE", "Protocol wrong type for socket"),
+#endif
+#if defined (ENOPROTOOPT)
+  ENTRY(ENOPROTOOPT, "ENOPROTOOPT", "Protocol not available"),
+#endif
+#if defined (EPROTONOSUPPORT)
+  ENTRY(EPROTONOSUPPORT, "EPROTONOSUPPORT", "Protocol not supported"),
+#endif
+#if defined (ESOCKTNOSUPPORT)
+  ENTRY(ESOCKTNOSUPPORT, "ESOCKTNOSUPPORT", "Socket type not supported"),
+#endif
+#if defined (EOPNOTSUPP)
+  ENTRY(EOPNOTSUPP, "EOPNOTSUPP", "Operation not supported on transport endpoint"),
+#endif
+#if defined (EPFNOSUPPORT)
+  ENTRY(EPFNOSUPPORT, "EPFNOSUPPORT", "Protocol family not supported"),
+#endif
+#if defined (EAFNOSUPPORT)
+  ENTRY(EAFNOSUPPORT, "EAFNOSUPPORT", "Address family not supported by protocol"),
+#endif
+#if defined (EADDRINUSE)
+  ENTRY(EADDRINUSE, "EADDRINUSE", "Address already in use"),
+#endif
+#if defined (EADDRNOTAVAIL)
+  ENTRY(EADDRNOTAVAIL, "EADDRNOTAVAIL","Cannot assign requested address"),
+#endif
+#if defined (ENETDOWN)
+  ENTRY(ENETDOWN, "ENETDOWN", "Network is down"),
+#endif
+#if defined (ENETUNREACH)
+  ENTRY(ENETUNREACH, "ENETUNREACH", "Network is unreachable"),
+#endif
+#if defined (ENETRESET)
+  ENTRY(ENETRESET, "ENETRESET", "Network dropped connection because of reset"),
+#endif
+#if defined (ECONNABORTED)
+  ENTRY(ECONNABORTED, "ECONNABORTED", "Software caused connection abort"),
+#endif
+#if defined (ECONNRESET)
+  ENTRY(ECONNRESET, "ECONNRESET", "Connection reset by peer"),
+#endif
+#if defined (ENOBUFS)
+  ENTRY(ENOBUFS, "ENOBUFS", "No buffer space available"),
+#endif
+#if defined (EISCONN)
+  ENTRY(EISCONN, "EISCONN", "Transport endpoint is already connected"),
+#endif
+#if defined (ENOTCONN)
+  ENTRY(ENOTCONN, "ENOTCONN", "Transport endpoint is not connected"),
+#endif
+#if defined (ESHUTDOWN)
+  ENTRY(ESHUTDOWN, "ESHUTDOWN", "Cannot send after transport endpoint shutdown"),
+#endif
+#if defined (ETOOMANYREFS)
+  ENTRY(ETOOMANYREFS, "ETOOMANYREFS", "Too many references: cannot splice"),
+#endif
+#if defined (ETIMEDOUT)
+  ENTRY(ETIMEDOUT, "ETIMEDOUT", "Connection timed out"),
+#endif
+#if defined (ECONNREFUSED)
+  ENTRY(ECONNREFUSED, "ECONNREFUSED", "Connection refused"),
+#endif
+#if defined (EHOSTDOWN)
+  ENTRY(EHOSTDOWN, "EHOSTDOWN", "Host is down"),
+#endif
+#if defined (EHOSTUNREACH)
+  ENTRY(EHOSTUNREACH, "EHOSTUNREACH", "No route to host"),
+#endif
+#if defined (EALREADY)
+  ENTRY(EALREADY, "EALREADY", "Operation already in progress"),
+#endif
+#if defined (EINPROGRESS)
+  ENTRY(EINPROGRESS, "EINPROGRESS", "Operation now in progress"),
+#endif
+#if defined (ESTALE)
+  ENTRY(ESTALE, "ESTALE", "Stale NFS file handle"),
+#endif
+#if defined (EUCLEAN)
+  ENTRY(EUCLEAN, "EUCLEAN", "Structure needs cleaning"),
+#endif
+#if defined (ENOTNAM)
+  ENTRY(ENOTNAM, "ENOTNAM", "Not a XENIX named type file"),
+#endif
+#if defined (ENAVAIL)
+  ENTRY(ENAVAIL, "ENAVAIL", "No XENIX semaphores available"),
+#endif
+#if defined (EISNAM)
+  ENTRY(EISNAM, "EISNAM", "Is a named type file"),
+#endif
+#if defined (EREMOTEIO)
+  ENTRY(EREMOTEIO, "EREMOTEIO", "Remote I/O error"),
+#endif
+  ENTRY(0, NULL, NULL)
+};
+
+#ifdef EVMSERR
+/* This is not in the table, because the numeric value of EVMSERR (32767)
+   lies outside the range of sys_errlist[].  */
+static struct { int value; const char *name, *msg; }
+  evmserr = { EVMSERR, "EVMSERR", "VMS-specific error" };
+#endif
+
+/* Translation table allocated and initialized at runtime.  Indexed by the
+   errno value to find the equivalent symbolic value. */
+
+static const char **error_names;
+static int num_error_names = 0;
+
+/* Translation table allocated and initialized at runtime, if it does not
+   already exist in the host environment.  Indexed by the errno value to find
+   the descriptive string.
+
+   We don't export it for use in other modules because even though it has the
+   same name, it differs from other implementations in that it is dynamically
+   initialized rather than statically initialized. */
+
+#ifndef HAVE_SYS_ERRLIST
+
+static int sys_nerr;
+static const char **sys_errlist;
+
+#else
+
+extern int sys_nerr;
+extern char *sys_errlist[];
+
+#endif
+
+
+/*
+
+NAME
+
+	init_error_tables -- initialize the name and message tables
+
+SYNOPSIS
+
+	static void init_error_tables ();
+
+DESCRIPTION
+
+	Using the error_table, which is initialized at compile time, generate
+	the error_names and the sys_errlist (if needed) tables, which are
+	indexed at runtime by a specific errno value.
+
+BUGS
+
+	The initialization of the tables may fail under low memory conditions,
+	in which case we don't do anything particularly useful, but we don't
+	bomb either.  Who knows, it might succeed at a later point if we free
+	some memory in the meantime.  In any case, the other routines know
+	how to deal with lack of a table after trying to initialize it.  This
+	may or may not be considered to be a bug, that we don't specifically
+	warn about this particular failure mode.
+
+*/
+
+static void
+init_error_tables ()
+{
+  const struct error_info *eip;
+  int nbytes;
+
+  /* If we haven't already scanned the error_table once to find the maximum
+     errno value, then go find it now. */
+
+  if (num_error_names == 0)
+    {
+      for (eip = error_table; eip -> name != NULL; eip++)
+	{
+	  if (eip -> value >= num_error_names)
+	    {
+	      num_error_names = eip -> value + 1;
+	    }
+	}
+    }
+
+  /* Now attempt to allocate the error_names table, zero it out, and then
+     initialize it from the statically initialized error_table. */
+
+  if (error_names == NULL)
+    {
+      nbytes = num_error_names * sizeof (char *);
+      if ((error_names = (const char **) malloc (nbytes)) != NULL)
+	{
+	  memset (error_names, 0, nbytes);
+	  for (eip = error_table; eip -> name != NULL; eip++)
+	    {
+	      error_names[eip -> value] = eip -> name;
+	    }
+	}
+    }
+
+#ifndef HAVE_SYS_ERRLIST
+
+  /* Now attempt to allocate the sys_errlist table, zero it out, and then
+     initialize it from the statically initialized error_table. */
+
+  if (sys_errlist == NULL)
+    {
+      nbytes = num_error_names * sizeof (char *);
+      if ((sys_errlist = (const char **) malloc (nbytes)) != NULL)
+	{
+	  memset (sys_errlist, 0, nbytes);
+	  sys_nerr = num_error_names;
+	  for (eip = error_table; eip -> name != NULL; eip++)
+	    {
+	      sys_errlist[eip -> value] = eip -> msg;
+	    }
+	}
+    }
+
+#endif
+
+}
+
+/*
+
+
+@deftypefn Extension int errno_max (void)
+
+Returns the maximum @code{errno} value for which a corresponding
+symbolic name or message is available.  Note that in the case where we
+use the @code{sys_errlist} supplied by the system, it is possible for
+there to be more symbolic names than messages, or vice versa.  In
+fact, the manual page for @code{perror(3C)} explicitly warns that one
+should check the size of the table (@code{sys_nerr}) before indexing
+it, since new error codes may be added to the system before they are
+added to the table.  Thus @code{sys_nerr} might be smaller than value
+implied by the largest @code{errno} value defined in @code{<errno.h>}.
+
+We return the maximum value that can be used to obtain a meaningful
+symbolic name or message.
+
+@end deftypefn
+
+*/
+
+int
+errno_max ()
+{
+  int maxsize;
+
+  if (error_names == NULL)
+    {
+      init_error_tables ();
+    }
+  maxsize = MAX (sys_nerr, num_error_names);
+  return (maxsize - 1);
+}
+
+#ifndef HAVE_STRERROR
+
+/*
+
+@deftypefn Supplemental char* strerror (int @var{errnoval})
+
+Maps an @code{errno} number to an error message string, the contents
+of which are implementation defined.  On systems which have the
+external variables @code{sys_nerr} and @code{sys_errlist}, these
+strings will be the same as the ones used by @code{perror}.
+
+If the supplied error number is within the valid range of indices for
+the @code{sys_errlist}, but no message is available for the particular
+error number, then returns the string @samp{Error @var{num}}, where
+@var{num} is the error number.
+
+If the supplied error number is not a valid index into
+@code{sys_errlist}, returns @code{NULL}.
+
+The returned string is only guaranteed to be valid only until the
+next call to @code{strerror}.
+
+@end deftypefn
+
+*/
+
+char *
+strerror (errnoval)
+  int errnoval;
+{
+  const char *msg;
+  static char buf[32];
+
+#ifndef HAVE_SYS_ERRLIST
+
+  if (error_names == NULL)
+    {
+      init_error_tables ();
+    }
+
+#endif
+
+  if ((errnoval < 0) || (errnoval >= sys_nerr))
+    {
+#ifdef EVMSERR
+      if (errnoval == evmserr.value)
+	msg = evmserr.msg;
+      else
+#endif
+      /* Out of range, just return NULL */
+      msg = NULL;
+    }
+  else if ((sys_errlist == NULL) || (sys_errlist[errnoval] == NULL))
+    {
+      /* In range, but no sys_errlist or no entry at this index. */
+      sprintf (buf, "Error %d", errnoval);
+      msg = buf;
+    }
+  else
+    {
+      /* In range, and a valid message.  Just return the message. */
+      msg = (char *) sys_errlist[errnoval];
+    }
+  
+  return (msg);
+}
+
+#endif	/* ! HAVE_STRERROR */
+
+
+/*
+
+@deftypefn Replacement {const char*} strerrno (int @var{errnum})
+
+Given an error number returned from a system call (typically returned
+in @code{errno}), returns a pointer to a string containing the
+symbolic name of that error number, as found in @code{<errno.h>}.
+
+If the supplied error number is within the valid range of indices for
+symbolic names, but no name is available for the particular error
+number, then returns the string @samp{Error @var{num}}, where @var{num}
+is the error number.
+
+If the supplied error number is not within the range of valid
+indices, then returns @code{NULL}.
+
+The contents of the location pointed to are only guaranteed to be
+valid until the next call to @code{strerrno}.
+
+@end deftypefn
+
+*/
+
+const char *
+strerrno (errnoval)
+  int errnoval;
+{
+  const char *name;
+  static char buf[32];
+
+  if (error_names == NULL)
+    {
+      init_error_tables ();
+    }
+
+  if ((errnoval < 0) || (errnoval >= num_error_names))
+    {
+#ifdef EVMSERR
+      if (errnoval == evmserr.value)
+	name = evmserr.name;
+      else
+#endif
+      /* Out of range, just return NULL */
+      name = NULL;
+    }
+  else if ((error_names == NULL) || (error_names[errnoval] == NULL))
+    {
+      /* In range, but no error_names or no entry at this index. */
+      sprintf (buf, "Error %d", errnoval);
+      name = (const char *) buf;
+    }
+  else
+    {
+      /* In range, and a valid name.  Just return the name. */
+      name = error_names[errnoval];
+    }
+
+  return (name);
+}
+
+/*
+
+@deftypefn Extension int strtoerrno (const char *@var{name})
+
+Given the symbolic name of a error number (e.g., @code{EACCES}), map it
+to an errno value.  If no translation is found, returns 0.
+
+@end deftypefn
+
+*/
+
+int
+strtoerrno (name)
+     const char *name;
+{
+  int errnoval = 0;
+
+  if (name != NULL)
+    {
+      if (error_names == NULL)
+	{
+	  init_error_tables ();
+	}
+      for (errnoval = 0; errnoval < num_error_names; errnoval++)
+	{
+	  if ((error_names[errnoval] != NULL) &&
+	      (strcmp (name, error_names[errnoval]) == 0))
+	    {
+	      break;
+	    }
+	}
+      if (errnoval == num_error_names)
+	{
+#ifdef EVMSERR
+	  if (strcmp (name, evmserr.name) == 0)
+	    errnoval = evmserr.value;
+	  else
+#endif
+	  errnoval = 0;
+	}
+    }
+  return (errnoval);
+}
+
+
+/* A simple little main that does nothing but print all the errno translations
+   if MAIN is defined and this file is compiled and linked. */
+
+#ifdef MAIN
+
+#include <stdio.h>
+
+int
+main ()
+{
+  int errn;
+  int errnmax;
+  const char *name;
+  const char *msg;
+  char *strerror ();
+
+  errnmax = errno_max ();
+  printf ("%d entries in names table.\n", num_error_names);
+  printf ("%d entries in messages table.\n", sys_nerr);
+  printf ("%d is max useful index.\n", errnmax);
+
+  /* Keep printing values until we get to the end of *both* tables, not
+     *either* table.  Note that knowing the maximum useful index does *not*
+     relieve us of the responsibility of testing the return pointer for
+     NULL. */
+
+  for (errn = 0; errn <= errnmax; errn++)
+    {
+      name = strerrno (errn);
+      name = (name == NULL) ? "<NULL>" : name;
+      msg = strerror (errn);
+      msg = (msg == NULL) ? "<NULL>" : msg;
+      printf ("%-4d%-18s%s\n", errn, name, msg);
+    }
+
+  return 0;
+}
+
+#endif