# HG changeset patch
# User Bruno Haible <bruno@clisp.org>
# Date 1208618796 -7200
# Node ID 9f8c455639fccaab10461bc4f9e355faa2d19b7a
# Parent  adf13947ae6c674e9cf70e36a37b215dd9abff5c
Fix rounding when a precision is given.

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,20 @@
+2008-04-19  Bruno Haible  <bruno@clisp.org>
+
+	Fix rounding when a precision is given.
+	* lib/vasnprintf.c (is_borderline): New function.
+	(VASNPRINTF): For %e and %g, consider replacing the digits 10....0 with
+	9...9x.
+	* tests/test-vasnprintf-posix.c (test_function): Test rounding with %f,
+	%e, %g.
+	* tests/test-vasprintf-posix.c (test_function): Likewise.
+	* tests/test-snprintf-posix.h (test_function): Likewise.
+	* tests/test-sprintf-posix.h (test_function): Likewise.
+	* tests/test-fprintf-posix.h (test_function): Test rounding with %f.
+	* tests/test-printf-posix.h (test_function): Likewise.
+	* tests/test-printf-posix.output: Update.
+	Reported by John Darrington <john@darrington.wattle.id.au> via
+	Ben Pfaff <blp@cs.stanford.edu>.
+
 2008-04-18  Simon Josefsson  <simon@josefsson.org>
 
 	* doc/posix-functions/strftime.texi (strftime): Clarify platform.
diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c
--- a/lib/vasnprintf.c
+++ b/lib/vasnprintf.c
@@ -1404,6 +1404,20 @@
 
 # endif
 
+/* Tests whether a string of digits consists of exactly PRECISION zeroes and
+   a single '1' digit.  */
+static int
+is_borderline (const char *digits, size_t precision)
+{
+  for (; precision > 0; precision--, digits++)
+    if (*digits != '0')
+      return 0;
+  if (*digits != '1')
+    return 0;
+  digits++;
+  return *digits == '\0';
+}
+
 #endif
 
 DCHAR_T *
@@ -2853,8 +2867,32 @@
 					  exponent += 1;
 					adjusted = 1;
 				      }
-
 				    /* Here ndigits = precision+1.  */
+				    if (is_borderline (digits, precision))
+				      {
+					/* Maybe the exponent guess was too high
+					   and a smaller exponent can be reached
+					   by turning a 10...0 into 9...9x.  */
+					char *digits2 =
+					  scale10_round_decimal_long_double (arg,
+									     (int)precision - exponent + 1);
+					if (digits2 == NULL)
+					  {
+					    free (digits);
+					    END_LONG_DOUBLE_ROUNDING ();
+					    goto out_of_memory;
+					  }
+					if (strlen (digits2) == precision + 1)
+					  {
+					    free (digits);
+					    digits = digits2;
+					    exponent -= 1;
+					  }
+					else
+					  free (digits2);
+				      }
+				    /* Here ndigits = precision+1.  */
+
 				    *p++ = digits[--ndigits];
 				    if ((flags & FLAG_ALT) || precision > 0)
 				      {
@@ -2966,6 +3004,30 @@
 					adjusted = 1;
 				      }
 				    /* Here ndigits = precision.  */
+				    if (is_borderline (digits, precision - 1))
+				      {
+					/* Maybe the exponent guess was too high
+					   and a smaller exponent can be reached
+					   by turning a 10...0 into 9...9x.  */
+					char *digits2 =
+					  scale10_round_decimal_long_double (arg,
+									     (int)(precision - 1) - exponent + 1);
+					if (digits2 == NULL)
+					  {
+					    free (digits);
+					    END_LONG_DOUBLE_ROUNDING ();
+					    goto out_of_memory;
+					  }
+					if (strlen (digits2) == precision)
+					  {
+					    free (digits);
+					    digits = digits2;
+					    exponent -= 1;
+					  }
+					else
+					  free (digits2);
+				      }
+				    /* Here ndigits = precision.  */
 
 				    /* Determine the number of trailing zeroes
 				       that have to be dropped.  */
@@ -3206,8 +3268,31 @@
 					  exponent += 1;
 					adjusted = 1;
 				      }
-
 				    /* Here ndigits = precision+1.  */
+				    if (is_borderline (digits, precision))
+				      {
+					/* Maybe the exponent guess was too high
+					   and a smaller exponent can be reached
+					   by turning a 10...0 into 9...9x.  */
+					char *digits2 =
+					  scale10_round_decimal_double (arg,
+									(int)precision - exponent + 1);
+					if (digits2 == NULL)
+					  {
+					    free (digits);
+					    goto out_of_memory;
+					  }
+					if (strlen (digits2) == precision + 1)
+					  {
+					    free (digits);
+					    digits = digits2;
+					    exponent -= 1;
+					  }
+					else
+					  free (digits2);
+				      }
+				    /* Here ndigits = precision+1.  */
+
 				    *p++ = digits[--ndigits];
 				    if ((flags & FLAG_ALT) || precision > 0)
 				      {
@@ -3332,6 +3417,29 @@
 					adjusted = 1;
 				      }
 				    /* Here ndigits = precision.  */
+				    if (is_borderline (digits, precision - 1))
+				      {
+					/* Maybe the exponent guess was too high
+					   and a smaller exponent can be reached
+					   by turning a 10...0 into 9...9x.  */
+					char *digits2 =
+					  scale10_round_decimal_double (arg,
+									(int)(precision - 1) - exponent + 1);
+					if (digits2 == NULL)
+					  {
+					    free (digits);
+					    goto out_of_memory;
+					  }
+					if (strlen (digits2) == precision)
+					  {
+					    free (digits);
+					    digits = digits2;
+					    exponent -= 1;
+					  }
+					else
+					  free (digits2);
+				      }
+				    /* Here ndigits = precision.  */
 
 				    /* Determine the number of trailing zeroes
 				       that have to be dropped.  */
diff --git a/tests/test-fprintf-posix.h b/tests/test-fprintf-posix.h
--- a/tests/test-fprintf-posix.h
+++ b/tests/test-fprintf-posix.h
@@ -1,5 +1,5 @@
 /* Test of POSIX compatible vsprintf() and sprintf() functions.
-   Copyright (C) 2007 Free Software Foundation, Inc.
+   Copyright (C) 2007-2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -65,6 +65,12 @@
   /* Precision.  */
   my_fprintf (stdout, "%.f %d\n", 1234.0, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_fprintf (stdout, "%.2f %d\n", 999.95, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_fprintf (stdout, "%.2f %d\n", 999.996, 33, 44, 55);
+
   /* A positive number.  */
   my_fprintf (stdout, "%Lf %d\n", 12.75L, 33, 44, 55);
 
@@ -83,6 +89,12 @@
   /* Precision.  */
   my_fprintf (stdout, "%.Lf %d\n", 1234.0L, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_fprintf (stdout, "%.2Lf %d\n", 999.95L, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_fprintf (stdout, "%.2Lf %d\n", 999.996L, 33, 44, 55);
+
   /* Test the support of the %F format directive.  */
 
   /* A positive number.  */
@@ -103,6 +115,12 @@
   /* Precision.  */
   my_fprintf (stdout, "%.F %d\n", 1234.0, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_fprintf (stdout, "%.2F %d\n", 999.95, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_fprintf (stdout, "%.2F %d\n", 999.996, 33, 44, 55);
+
   /* A positive number.  */
   my_fprintf (stdout, "%LF %d\n", 12.75L, 33, 44, 55);
 
@@ -121,6 +139,12 @@
   /* Precision.  */
   my_fprintf (stdout, "%.LF %d\n", 1234.0L, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_fprintf (stdout, "%.2LF %d\n", 999.95L, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_fprintf (stdout, "%.2LF %d\n", 999.996L, 33, 44, 55);
+
   /* Test the support of the POSIX/XSI format strings with positions.  */
 
   my_fprintf (stdout, "%2$d %1$d\n", 33, 55);
diff --git a/tests/test-printf-posix.h b/tests/test-printf-posix.h
--- a/tests/test-printf-posix.h
+++ b/tests/test-printf-posix.h
@@ -1,5 +1,5 @@
 /* Test of POSIX compatible vsprintf() and sprintf() functions.
-   Copyright (C) 2007 Free Software Foundation, Inc.
+   Copyright (C) 2007-2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -67,6 +67,12 @@
   /* Precision.  */
   my_printf ("%.f %d\n", 1234.0, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_printf ("%.2f %d\n", 999.95, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_printf ("%.2f %d\n", 999.996, 33, 44, 55);
+
   /* A positive number.  */
   my_printf ("%Lf %d\n", 12.75L, 33, 44, 55);
 
@@ -85,6 +91,12 @@
   /* Precision.  */
   my_printf ("%.Lf %d\n", 1234.0L, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_printf ("%.2Lf %d\n", 999.95L, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_printf ("%.2Lf %d\n", 999.996L, 33, 44, 55);
+
   /* Test the support of the %F format directive.  */
 
   /* A positive number.  */
@@ -105,6 +117,12 @@
   /* Precision.  */
   my_printf ("%.F %d\n", 1234.0, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_printf ("%.2F %d\n", 999.95, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_printf ("%.2F %d\n", 999.996, 33, 44, 55);
+
   /* A positive number.  */
   my_printf ("%LF %d\n", 12.75L, 33, 44, 55);
 
@@ -123,6 +141,12 @@
   /* Precision.  */
   my_printf ("%.LF %d\n", 1234.0L, 33, 44, 55);
 
+  /* Precision with no rounding.  */
+  my_printf ("%.2LF %d\n", 999.95L, 33, 44, 55);
+
+  /* Precision with rounding.  */
+  my_printf ("%.2LF %d\n", 999.996L, 33, 44, 55);
+
   /* Test the support of the POSIX/XSI format strings with positions.  */
 
   my_printf ("%2$d %1$d\n", 33, 55);
diff --git a/tests/test-printf-posix.output b/tests/test-printf-posix.output
--- a/tests/test-printf-posix.output
+++ b/tests/test-printf-posix.output
@@ -11,22 +11,30 @@
 0.000000 33
 00001234.000000 33
 1234 33
+999.95 33
+1000.00 33
 12.750000 33
 1234567.000000 33
 -0.031250 33
 0.000000 33
 00001234.000000 33
 1234 33
+999.95 33
+1000.00 33
 12.750000 33
 1234567.000000 33
 -0.031250 33
 0.000000 33
 00001234.000000 33
 1234 33
+999.95 33
+1000.00 33
 12.750000 33
 1234567.000000 33
 -0.031250 33
 0.000000 33
 00001234.000000 33
 1234 33
+999.95 33
+1000.00 33
 55 33
diff --git a/tests/test-snprintf-posix.h b/tests/test-snprintf-posix.h
--- a/tests/test-snprintf-posix.h
+++ b/tests/test-snprintf-posix.h
@@ -1004,6 +1004,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2f %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2f %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[100];
     int retval =
@@ -1338,6 +1354,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2Lf %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2Lf %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %F format directive.  */
 
   { /* A positive number.  */
@@ -1434,6 +1466,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2F %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2F %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[100];
     int retval =
@@ -1528,6 +1576,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2LF %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.2LF %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %e format directive.  */
 
   { /* A positive number.  */
@@ -1802,6 +1866,24 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.4e %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0
+	    || strcmp (result, "9.9995e+002 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.4e %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0
+	    || strcmp (result, "1.0000e+003 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[100];
     int retval =
@@ -2138,6 +2220,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.4Le %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.4Le %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %g format directive.  */
 
   { /* A positive number.  */
@@ -2401,6 +2499,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.5g %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.5g %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[100];
     int retval =
@@ -2737,6 +2851,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.5Lg %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_snprintf (result, sizeof (result), "%.5Lg %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %n format directive.  */
 
   {
diff --git a/tests/test-sprintf-posix.h b/tests/test-sprintf-posix.h
--- a/tests/test-sprintf-posix.h
+++ b/tests/test-sprintf-posix.h
@@ -984,6 +984,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2f %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2f %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[1000];
     int retval =
@@ -1312,6 +1328,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2Lf %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2Lf %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %F format directive.  */
 
   { /* A positive number.  */
@@ -1408,6 +1440,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2F %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2F %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[1000];
     int retval =
@@ -1502,6 +1550,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2LF %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.2LF %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %e format directive.  */
 
   { /* A positive number.  */
@@ -1776,6 +1840,24 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.4e %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0
+	    || strcmp (result, "9.9995e+002 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.4e %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0
+	    || strcmp (result, "1.0000e+003 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[1000];
     int retval =
@@ -2112,6 +2194,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.4Le %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.4Le %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %g format directive.  */
 
   { /* A positive number.  */
@@ -2375,6 +2473,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.5g %d", 999.951, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.5g %d", 999.996, 33, 44, 55);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   { /* A positive number.  */
     char result[1000];
     int retval =
@@ -2711,6 +2825,22 @@
     ASSERT (retval == strlen (result));
   }
 
+  { /* Precision with no rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.5Lg %d", 999.951L, 33, 44, 55);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
+  { /* Precision with rounding.  */
+    char result[100];
+    int retval =
+      my_sprintf (result, "%.5Lg %d", 999.996L, 33, 44, 55);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (retval == strlen (result));
+  }
+
   /* Test the support of the %n format directive.  */
 
   {
diff --git a/tests/test-vasnprintf-posix.c b/tests/test-vasnprintf-posix.c
--- a/tests/test-vasnprintf-posix.c
+++ b/tests/test-vasnprintf-posix.c
@@ -1189,6 +1189,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2f %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2f %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     size_t length;
     char *result =
@@ -1569,6 +1589,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2Lf %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2Lf %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %F format directive.  */
 
   { /* A positive number.  */
@@ -1687,6 +1727,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2F %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2F %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     size_t length;
     char *result =
@@ -1803,6 +1863,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2LF %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.2LF %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %e format directive.  */
 
   { /* A positive number.  */
@@ -2116,6 +2196,28 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.4e %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0
+	    || strcmp (result, "9.9995e+002 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.4e %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0
+	    || strcmp (result, "1.0000e+003 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     size_t length;
     char *result =
@@ -2506,6 +2608,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.4Le %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.4Le %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %g format directive.  */
 
   { /* A positive number.  */
@@ -2809,6 +2931,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.5g %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.5g %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     size_t length;
     char *result =
@@ -3199,6 +3341,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.5Lg %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    size_t length;
+    char *result =
+      my_asnprintf (NULL, &length, "%.5Lg %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (length == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %n format directive.  */
 
   {
diff --git a/tests/test-vasprintf-posix.c b/tests/test-vasprintf-posix.c
--- a/tests/test-vasprintf-posix.c
+++ b/tests/test-vasprintf-posix.c
@@ -1170,6 +1170,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2f %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2f %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     char *result;
     int retval =
@@ -1550,6 +1570,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2Lf %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2Lf %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %F format directive.  */
 
   { /* A positive number.  */
@@ -1668,6 +1708,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2F %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2F %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     char *result;
     int retval =
@@ -1784,6 +1844,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2LF %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.2LF %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000.00 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %e format directive.  */
 
   { /* A positive number.  */
@@ -2097,6 +2177,28 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.4e %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0
+	    || strcmp (result, "9.9995e+002 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.4e %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0
+	    || strcmp (result, "1.0000e+003 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     char *result;
     int retval =
@@ -2487,6 +2589,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.4Le %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "9.9995e+02 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.4Le %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1.0000e+03 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %g format directive.  */
 
   { /* A positive number.  */
@@ -2790,6 +2912,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.5g %d", 999.951, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.5g %d", 999.996, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   { /* A positive number.  */
     char *result;
     int retval =
@@ -3180,6 +3322,26 @@
     free (result);
   }
 
+  { /* Precision with no rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.5Lg %d", 999.951L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "999.95 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
+  { /* Precision with rounding.  */
+    char *result;
+    int retval =
+      my_asprintf (&result, "%.5Lg %d", 999.996L, 33, 44, 55);
+    ASSERT (result != NULL);
+    ASSERT (strcmp (result, "1000 33") == 0);
+    ASSERT (retval == strlen (result));
+    free (result);
+  }
+
   /* Test the support of the %n format directive.  */
 
   {