diff -Naurd mpfr-3.0.0-a/PATCHES mpfr-3.0.0-b/PATCHES
--- mpfr-3.0.0-a/PATCHES	2010-06-23 11:02:49.000000000 +0000
+++ mpfr-3.0.0-b/PATCHES	2010-06-23 11:03:36.000000000 +0000
@@ -0,0 +1 @@
+mpfr_out_str
diff -Naurd mpfr-3.0.0-a/VERSION mpfr-3.0.0-b/VERSION
--- mpfr-3.0.0-a/VERSION	2010-06-10 11:00:14.000000000 +0000
+++ mpfr-3.0.0-b/VERSION	2010-06-23 11:03:20.000000000 +0000
@@ -1 +1 @@
-3.0.0
+3.0.0-p1
diff -Naurd mpfr-3.0.0-a/mpfr.h mpfr-3.0.0-b/mpfr.h
--- mpfr-3.0.0-a/mpfr.h	2010-06-10 11:00:14.000000000 +0000
+++ mpfr-3.0.0-b/mpfr.h	2010-06-23 11:03:20.000000000 +0000
@@ -27,7 +27,7 @@
 #define MPFR_VERSION_MAJOR 3
 #define MPFR_VERSION_MINOR 0
 #define MPFR_VERSION_PATCHLEVEL 0
-#define MPFR_VERSION_STRING "3.0.0"
+#define MPFR_VERSION_STRING "3.0.0-p1"
 
 /* Macros dealing with MPFR VERSION */
 #define MPFR_VERSION_NUM(a,b,c) (((a) << 16L) | ((b) << 8) | (c))
diff -Naurd mpfr-3.0.0-a/mpfr.texi mpfr-3.0.0-b/mpfr.texi
--- mpfr-3.0.0-a/mpfr.texi	2010-06-10 11:00:14.000000000 +0000
+++ mpfr-3.0.0-b/mpfr.texi	2010-06-23 11:03:12.000000000 +0000
@@ -2050,7 +2050,7 @@
 are printed. If @var{base} is greater than 10, @samp{@@} will be used
 instead of @samp{e} as exponent delimiter.
 
-Return the number of bytes written, or if an error occurred, return 0.
+Return the number of characters written, or if an error occurred, return 0.
 @end deftypefun
 
 @deftypefun size_t mpfr_inp_str (mpfr_t @var{rop}, FILE *@var{stream}, int @var{base}, mpfr_rnd_t @var{rnd})
diff -Naurd mpfr-3.0.0-a/out_str.c mpfr-3.0.0-b/out_str.c
--- mpfr-3.0.0-a/out_str.c	2010-06-10 11:00:14.000000000 +0000
+++ mpfr-3.0.0-b/out_str.c	2010-06-23 11:03:12.000000000 +0000
@@ -22,6 +22,16 @@
 
 #include "mpfr-impl.h"
 
+/* Warning! S should not contain "%". */
+#define OUT_STR_RET(S)                          \
+  do                                            \
+    {                                           \
+      int r;                                    \
+      r = fprintf (stream, (S));                \
+      return r < 0 ? 0 : r;                     \
+    }                                           \
+  while (0)
+
 size_t
 mpfr_out_str (FILE *stream, int base, size_t n_digits, mpfr_srcptr op,
               mpfr_rnd_t rnd_mode)
@@ -29,6 +39,7 @@
   char *s, *s0;
   size_t l;
   mpfr_exp_t e;
+  int err;
 
   MPFR_ASSERTN (base >= 2 && base <= 62);
 
@@ -36,37 +47,16 @@
   if (stream == NULL)
     stream = stdout;
 
-  if (MPFR_IS_NAN(op))
-    {
-      fprintf (stream, "@NaN@");
-      return 3;
-    }
-
-  if (MPFR_IS_INF(op))
-    {
-      if (MPFR_SIGN(op) > 0)
-        {
-          fprintf (stream, "@Inf@");
-          return 3;
-        }
-      else
-        {
-          fprintf (stream, "-@Inf@");
-          return 4;
-        }
-    }
-
-  if (MPFR_IS_ZERO(op))
+  if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (op)))
     {
-      if (MPFR_SIGN(op) > 0)
-        {
-          fprintf(stream, "0");
-          return 1;
-        }
+      if (MPFR_IS_NAN (op))
+        OUT_STR_RET ("@NaN@");
+      else if (MPFR_IS_INF (op))
+        OUT_STR_RET (MPFR_IS_POS (op) ? "@Inf@" : "-@Inf@");
       else
         {
-          fprintf(stream, "-0");
-          return 2;
+          MPFR_ASSERTD (MPFR_IS_ZERO (op));
+          OUT_STR_RET (MPFR_IS_POS (op) ? "0" : "-0");
         }
     }
 
@@ -77,21 +67,31 @@
 
   l = strlen (s) + 1; /* size of allocated block returned by mpfr_get_str
                          - may be incorrect, as only an upper bound? */
-  if (*s == '-')
-    fputc (*s++, stream);
 
-  /* outputs mantissa */
-  fputc (*s++, stream); e--; /* leading digit */
-  fputc ((unsigned char) MPFR_DECIMAL_POINT, stream);
-  fputs (s, stream);         /* rest of mantissa */
+  /* outputs possible sign and significand */
+  err = (*s == '-' && fputc (*s++, stream) == EOF)
+    || fputc (*s++, stream) == EOF  /* leading digit */
+    || fputc ((unsigned char) MPFR_DECIMAL_POINT, stream) == EOF
+    || fputs (s, stream) == EOF;     /* trailing significand */
   (*__gmp_free_func) (s0, l);
+  if (MPFR_UNLIKELY (err))
+    return 0;
+
+  e--;  /* due to the leading digit */
 
   /* outputs exponent */
   if (e)
     {
+      int r;
+
       MPFR_ASSERTN(e >= LONG_MIN);
       MPFR_ASSERTN(e <= LONG_MAX);
-      l += fprintf (stream, (base <= 10 ? "e%ld" : "@%ld"), (long) e);
+
+      r = fprintf (stream, (base <= 10 ? "e%ld" : "@%ld"), (long) e);
+      if (MPFR_UNLIKELY (r < 0))
+        return 0;
+
+      l += r;
     }
 
   return l;
diff -Naurd mpfr-3.0.0-a/tests/tout_str.c mpfr-3.0.0-b/tests/tout_str.c
--- mpfr-3.0.0-a/tests/tout_str.c	2010-06-10 11:00:13.000000000 +0000
+++ mpfr-3.0.0-b/tests/tout_str.c	2010-06-23 11:03:12.000000000 +0000
@@ -46,22 +46,54 @@
 special (void)
 {
   mpfr_t x;
+  unsigned int n;
 
   mpfr_init (x);
 
   mpfr_set_nan (x);
-  mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  n = mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  if (n != 5)
+    {
+      printf ("Error: mpfr_out_str (file, 10, 0, NaN, MPFR_RNDN) wrote %u "
+              "characters instead of 5.\n", n);
+      exit (1);
+    }
 
   mpfr_set_inf (x, 1);
-  mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  n = mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  if (n != 5)
+    {
+      printf ("Error: mpfr_out_str (file, 10, 0, +Inf, MPFR_RNDN) wrote %u "
+               "characters instead of 5.\n", n);
+      exit (1);
+    }
 
   mpfr_set_inf (x, -1);
-  mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  n = mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  if (n != 6)
+    {
+      printf ("Error: mpfr_out_str (file, 10, 0, -Inf, MPFR_RNDN) wrote %u "
+               "characters instead of 6.\n", n);
+      exit (1);
+    }
 
   mpfr_set_ui (x, 0, MPFR_RNDN);
-  mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  n = mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  if (n != 1)
+    {
+      printf ("Error: mpfr_out_str (file, 10, 0, +0, MPFR_RNDN) wrote %u "
+               "characters instead of 1.\n", n);
+      exit (1);
+    }
+
   mpfr_neg (x, x, MPFR_RNDN);
-  mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  n = mpfr_out_str (fout, 10, 0, x, MPFR_RNDN);
+  if (n != 2)
+    {
+      printf ("Error: mpfr_out_str (file, 10, 0, -0, MPFR_RNDN) wrote %u "
+               "characters instead of 2.\n", n);
+      exit (1);
+    }
 
   mpfr_clear (x);
 }
diff -Naurd mpfr-3.0.0-a/version.c mpfr-3.0.0-b/version.c
--- mpfr-3.0.0-a/version.c	2010-06-10 11:00:14.000000000 +0000
+++ mpfr-3.0.0-b/version.c	2010-06-23 11:03:20.000000000 +0000
@@ -25,5 +25,5 @@
 const char *
 mpfr_get_version (void)
 {
-  return "3.0.0";
+  return "3.0.0-p1";
 }