1 /* Implement the vsnprintf function.
2 Copyright (C) 2003, 2004, 2005 Free Software Foundation, Inc.
3 Written by Kaveh R. Ghazi <ghazi@caip.rutgers.edu>.
5 This file is part of the libiberty library. This library is free
6 software; you can redistribute it and/or modify it under the
7 terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option)
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
20 As a special exception, if you link this library with files
21 compiled with a GNU compiler to produce an executable, this does not cause
22 the resulting executable to be covered by the GNU General Public License.
23 This exception does not however invalidate any other reasons why
24 the executable file might be covered by the GNU General Public License. */
28 @deftypefn Supplemental int vsnprintf (char *@var{buf}, size_t @var{n}, const char *@var{format}, va_list @var{ap})
30 This function is similar to vsprintf, but it will print at most
31 @var{n} characters. On error the return value is -1, otherwise it
32 returns the number of characters that would have been printed had
33 @var{n} been sufficiently large, regardless of the actual value of
34 @var{n}. Note some pre-C99 system libraries do not implement this
35 correctly so users cannot generally rely on the return value if the
36 system version of this function is used.
53 #include "libiberty.h"
55 /* This implementation relies on a working vasprintf. */
57 vsnprintf (char *s
, size_t n
, const char *format
, va_list ap
)
60 int result
= vasprintf (&buf
, format
, ap
);
70 result
= strlen (buf
);
73 if ((long) n
> result
)
74 memcpy (s
, buf
, result
+1);
86 /* Set the buffer to a known state. */
87 #define CLEAR(BUF) do { memset ((BUF), 'X', sizeof (BUF)); (BUF)[14] = '\0'; } while (0)
89 #define VERIFY(P) do { if (!(P)) abort(); } while (0)
91 static int ATTRIBUTE_PRINTF_3
92 checkit (char *s
, size_t n
, const char *format
, ...)
96 VA_FIXEDARG (ap
, char *, s
);
97 VA_FIXEDARG (ap
, size_t, n
);
98 VA_FIXEDARG (ap
, const char *, format
);
99 result
= vsnprintf (s
, n
, format
, ap
);
104 extern int main (void);
112 status
= checkit (buf
, 10, "%s:%d", "foobar", 9);
113 VERIFY (status
==8 && memcmp (buf
, "foobar:9\0XXXXX\0", 15) == 0);
116 status
= checkit (buf
, 9, "%s:%d", "foobar", 9);
117 VERIFY (status
==8 && memcmp (buf
, "foobar:9\0XXXXX\0", 15) == 0);
120 status
= checkit (buf
, 8, "%s:%d", "foobar", 9);
121 VERIFY (status
==8 && memcmp (buf
, "foobar:\0XXXXXX\0", 15) == 0);
124 status
= checkit (buf
, 7, "%s:%d", "foobar", 9);
125 VERIFY (status
==8 && memcmp (buf
, "foobar\0XXXXXXX\0", 15) == 0);
128 status
= checkit (buf
, 6, "%s:%d", "foobar", 9);
129 VERIFY (status
==8 && memcmp (buf
, "fooba\0XXXXXXXX\0", 15) == 0);
132 status
= checkit (buf
, 2, "%s:%d", "foobar", 9);
133 VERIFY (status
==8 && memcmp (buf
, "f\0XXXXXXXXXXXX\0", 15) == 0);
136 status
= checkit (buf
, 1, "%s:%d", "foobar", 9);
137 VERIFY (status
==8 && memcmp (buf
, "\0XXXXXXXXXXXXX\0", 15) == 0);
140 status
= checkit (buf
, 0, "%s:%d", "foobar", 9);
141 VERIFY (status
==8 && memcmp (buf
, "XXXXXXXXXXXXXX\0", 15) == 0);
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