Update.

1999-06-23  Ulrich Drepper  <drepper@cygnus.com>

	* manual/arith.texi: Document restriction of ndigit parameter of
	ecvt and friends.
	* misc/efgcvt.c: Define NDIGIT_MAX.
	(gcvt): Limit precision in sprintf call to NDIGIT_MAX.
	Do not dynamically allocate the static buffers.  They are small enough.
	* misc/efgcvt_r.c: Define NDIGIT_MAX.
	(fcvt_r): Limit precision in snprintf call to NDIGIT_MAX.
	* misc/qefgcvt.c: Define NDIGIT_MAX.
	* misc/qefgcvt_r.c: Likewise.
	* misc/tst-efgcvt.c (special): Add test for large ndigit parameter.

ChangeLog

@@ -1,3 +1,16 @@
+1999-06-23  Ulrich Drepper  <drepper@cygnus.com>
+
+	* manual/arith.texi: Document restriction of ndigit parameter of
+	ecvt and friends.
+	* misc/efgcvt.c: Define NDIGIT_MAX.
+	(gcvt): Limit precision in sprintf call to NDIGIT_MAX.
+	Do not dynamically allocate the static buffers.  They are small enough.
+	* misc/efgcvt_r.c: Define NDIGIT_MAX.
+	(fcvt_r): Limit precision in snprintf call to NDIGIT_MAX.
+	* misc/qefgcvt.c: Define NDIGIT_MAX.
+	* misc/qefgcvt_r.c: Likewise.
+	* misc/tst-efgcvt.c (special): Add test for large ndigit parameter.
+
 1999-06-23  Zack Weinberg  <zack@rabi.columbia.edu>
 
 	* libio/stdio.h: Define stdin, stdout, stderr as macros.

manual/arith.texi

@@ -2199,6 +2199,9 @@ index in the string of the first digit after the decimal point.
 @var{neg} is set to a nonzero value if @var{value} is negative, zero
 otherwise.
 
+If @var{ndigit} decimal digits would exceed the precision of a
+@code{double} it is reduced to a system-specific value.
+
 The returned string is statically allocated and overwritten by each call
 to @code{ecvt}.
 
@@ -2220,6 +2223,9 @@ left of the decimal point.  For example, if @var{ndigit} is @code{-1},
 negative and larger than the number of digits to the left of the decimal
 point in @var{value}, @var{value} will be rounded to one significant digit.
 
+If @var{ndigit} decimal digits would exceed the precision of a
+@code{double} it is reduced to a system-specific value.
+
 The returned string is statically allocated and overwritten by each call
 to @code{fcvt}.
 @end deftypefun
@@ -2230,6 +2236,9 @@ to @code{fcvt}.
 @code{gcvt} is functionally equivalent to @samp{sprintf(buf, "%*g",
 ndigit, value}.  It is provided only for compatibility's sake.  It
 returns @var{buf}.
+
+If @var{ndigit} decimal digits would exceed the precision of a
+@code{double} it is reduced to a system-specific value.
 @end deftypefun
 
 As extensions, the GNU C library provides versions of these three
@@ -2238,22 +2247,25 @@ functions that take @code{long double} arguments.
 @comment stdlib.h
 @comment GNU
 @deftypefun {char *} qecvt (long double @var{value}, int @var{ndigit}, int *@var{decpt}, int *@var{neg})
-This function is equivalent to @code{ecvt} except that it
+This function is equivalent to @code{ecvt} except that it takes a
-takes a @code{long double} for the first parameter.
+@code{long double} for the first parameter and that @var{ndigit} is
+restricted by the precision of a @code{long double}.
 @end deftypefun
 
 @comment stdlib.h
 @comment GNU
 @deftypefun {char *} qfcvt (long double @var{value}, int @var{ndigit}, int @var{decpt}, int *@var{neg})
 This function is equivalent to @code{fcvt} except that it
-takes a @code{long double} for the first parameter.
+takes a @code{long double} for the first parameter and that @var{ndigit} is
+restricted by the precision of a @code{long double}.
 @end deftypefun
 
 @comment stdlib.h
 @comment GNU
 @deftypefun {char *} qgcvt (long double @var{value}, int @var{ndigit}, char *@var{buf})
-This function is equivalent to @code{gcvt} except that it
+This function is equivalent to @code{gcvt} except that it takes a
-takes a @code{long double} for the first parameter.
+@code{long double} for the first parameter and that @var{ndigit} is
+restricted by the precision of a @code{long double}.
 @end deftypefun
 
 

misc/efgcvt.c

@@ -1,5 +1,5 @@
 /* Compatibility functions for floating point formatting.
-   Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1996, 1997, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -19,6 +19,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/param.h>
 #include <float.h>
 #include <bits/libc-lock.h>
 
@@ -29,6 +30,7 @@
 /* Actually we have to write (DBL_DIG + log10 (DBL_MAX_10_EXP)) but we
    don't have log10 available in the preprocessor.  */
 # define MAXDIG (DBL_DIG + 3)
+# define NDIGIT_MAX DBL_DIG
 #endif
 
 #define APPEND(a, b) APPEND2 (a, b)
@@ -39,30 +41,15 @@
 #define ECVT_BUFFER APPEND (FUNC_PREFIX, ecvt_buffer)
 
 
-static char *FCVT_BUFFER;
+static char FCVT_BUFFER[MAXDIG];
-static char *ECVT_BUFFER;
+static char ECVT_BUFFER[MAXDIG];
 
 
-static void
-APPEND (FUNC_PREFIX, fcvt_allocate) (void)
-{
-  FCVT_BUFFER = (char *) malloc (MAXDIG);
-}
-
 char *
 APPEND (FUNC_PREFIX, fcvt) (value, ndigit, decpt, sign)
      FLOAT_TYPE value;
      int ndigit, *decpt, *sign;
 {
-  __libc_once_define (static, once);
-  __libc_once (once, APPEND (FUNC_PREFIX, fcvt_allocate));
-
-  if (FCVT_BUFFER == NULL)
-    /* If no core is available we don't have a chance to run the
-       program successfully and so returning NULL is an acceptable
-       result.  */
-    return NULL;
-
   (void) APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign,
 				       FCVT_BUFFER, MAXDIG);
 
@@ -70,26 +57,11 @@ APPEND (FUNC_PREFIX, fcvt) (value, ndigit, decpt, sign)
 }
 
 
-static void
-APPEND (FUNC_PREFIX, ecvt_allocate) (void)
-{
-  ECVT_BUFFER = (char *) malloc (MAXDIG);
-}
-
 char *
 APPEND (FUNC_PREFIX, ecvt) (value, ndigit, decpt, sign)
      FLOAT_TYPE value;
      int ndigit, *decpt, *sign;
 {
-  __libc_once_define (static, once);
-  __libc_once (once, APPEND (FUNC_PREFIX, ecvt_allocate));
-
-  if (ECVT_BUFFER == NULL)
-    /* If no core is available we don't have a chance to run the
-       program successfully and so returning NULL is an acceptable
-       result.  */
-    return NULL;
-
   (void) APPEND (FUNC_PREFIX, ecvt_r) (value, ndigit, decpt, sign,
 				       ECVT_BUFFER, MAXDIG);
 
@@ -102,21 +74,6 @@ APPEND (FUNC_PREFIX, gcvt) (value, ndigit, buf)
      int ndigit;
      char *buf;
 {
-  sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", ndigit, value);
+  sprintf (buf, "%.*" FLOAT_FMT_FLAG "g", MIN (ndigit, NDIGIT_MAX), value);
   return buf;
 }
-
-
-/* Make sure the memory is freed if the programs ends while in
-   memory-debugging mode and something actually was allocated.  */
-static void
-__attribute__ ((unused))
-free_mem (void)
-{
-  if (FCVT_BUFFER != NULL)
-    free (FCVT_BUFFER);
-  if (ECVT_BUFFER != NULL)
-    free (ECVT_BUFFER);
-}
-
-text_set_element (__libc_subfreeres, free_mem);

misc/efgcvt_r.c

@@ -1,5 +1,5 @@
 /* Compatibility functions for floating point formatting, reentrant versions.
-   Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.
+   Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -26,10 +26,11 @@
 #include <sys/param.h>
 
 #ifndef FLOAT_TYPE
-#define FLOAT_TYPE double
+# define FLOAT_TYPE double
-#define FUNC_PREFIX
+# define FUNC_PREFIX
-#define FLOAT_FMT_FLAG
+# define FLOAT_FMT_FLAG
-#define FLOAT_NAME_EXT
+# define FLOAT_NAME_EXT
+# define NDIGIT_MAX DBL_DIG
 #endif
 
 #define APPEND(a, b) APPEND2 (a, b)
@@ -87,7 +88,8 @@ APPEND (FUNC_PREFIX, fcvt_r) (value, ndigit, decpt, sign, buf, len)
     /* Value is Inf or NaN.  */
     *sign = 0;
 
-  n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", ndigit, value);
+  n = __snprintf (buf, len, "%.*" FLOAT_FMT_FLAG "f", MIN (ndigit, NDIGIT_MAX),
+		  value);
   if (n < 0)
     return -1;
 

misc/qefgcvt.c

@@ -1,5 +1,5 @@
 /* Compatibility functions for floating point formatting, long double version.
-   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -24,5 +24,6 @@
    we don't have log10 available in the preprocessor.  Since we cannot
    assume anything on the used `long double' format be generous.  */
 #define MAXDIG (LDBL_DIG + 12)
+#define NDIGIT_MAX LDBL_DIG
 
 #include "efgcvt.c"

misc/qefgcvt_r.c

@@ -1,6 +1,6 @@
 /* Compatibility functions for floating point formatting, reentrant,
    long double versions.
-   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+   Copyright (C) 1996, 1997, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -22,5 +22,6 @@
 #define FUNC_PREFIX q
 #define FLOAT_FMT_FLAG "L"
 #define FLOAT_NAME_EXT l
+# define NDIGIT_MAX LDBL_DIG
 
 #include "efgcvt_r.c"

misc/tst-efgcvt.c

@@ -1,4 +1,4 @@
-/* Copyright (C) 1998 Free Software Foundation, Inc.
+/* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -131,6 +131,10 @@ special (void)
   if (sign != 0 || strcmp (p, "inf") != 0)
     output_error ("ecvt", NAN, 10, "inf", 0, 0, p, decpt, sign);
 
+  /* Simply make sure these calls with large NDIGITs don't crash.  */
+  (void) ecvt (123.456, 10000, &decpt, &sign);
+  (void) fcvt (123.456, 10000, &decpt, &sign);
+
 }