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可变参数的问题
gcc的实现
/*
@deftypefn Supplemental int vprintf (const char *@var{format}, va_list @var{ap})
@deftypefnx Supplemental int vfprintf (FILE *@var{stream}, const char *@var{format}, va_list @var{ap})
@deftypefnx Supplemental int vsprintf (char *@var{str}, const char *@var{format}, va_list @var{ap})
These functions are the same as @code{printf}, @code{fprintf}, and
@code{sprintf}, respectively, except that they are called with a
@code{va_list} instead of a variable number of arguments. Note that
they do not call @code{va_end}; this is the application's
responsibility. In @libib{} they are implemented in terms of the
nonstandard but common function @code{_doprnt}.
@end deftypefn
*/
#include <ansidecl.h>;
#ifdef ANSI_PROTOTYPES
#include <stdarg.h>;
#else
#include <varargs.h>;
#endif
#include <stdio.h>;
#undef vprintf
int
vprintf (format, ap)
const char *format;
va_list ap;
{
return vfprintf (stdout, format, ap);
}
/* Provide a version of _doprnt in terms of fprintf.
Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
Contributed by Kaveh Ghazi (ghazi@caip.rutgers.edu) 3/29/98
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 the
Free Software Foundation; either version 2, or (at your option) any
later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#include "config.h"
#include "ansidecl.h"
#include "safe-ctype.h"
#include <stdio.h>;
#ifdef ANSI_PROTOTYPES
#include <stdarg.h>;
#else
#include <varargs.h>;
#endif
#ifdef HAVE_STRING_H
#include <string.h>;
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>;
#endif
#undef _doprnt
#ifdef HAVE__DOPRNT
#define TEST
#endif
#ifdef TEST /* Make sure to use the internal one. */
#define _doprnt my_doprnt
#endif
#define COPY_VA_INT \
do { \
const int value = abs (va_arg (ap, int)); \
char buf[32]; \
ptr++; /* Go past the asterisk. */ \
*sptr = '\0'; /* NULL terminate sptr. */ \
sprintf(buf, "%d", value); \
strcat(sptr, buf); \
while (*sptr) sptr++; \
} while (0)
#define PRINT_CHAR(CHAR) \
do { \
putc(CHAR, stream); \
ptr++; \
total_printed++; \
continue; \
} while (0)
#define PRINT_TYPE(TYPE) \
do { \
int result; \
TYPE value = va_arg (ap, TYPE); \
*sptr++ = *ptr++; /* Copy the type specifier. */ \
*sptr = '\0'; /* NULL terminate sptr. */ \
result = fprintf(stream, specifier, value); \
if (result == -1) \
return -1; \
else \
{ \
total_printed += result; \
continue; \
} \
} while (0)
int
_doprnt (format, ap, stream)
const char * format;
va_list ap;
FILE * stream;
{
const char * ptr = format;
char specifier[128];
int total_printed = 0;
while (*ptr != '\0')
{
if (*ptr != '%') /* While we have regular characters, print them. */
PRINT_CHAR(*ptr);
else /* We got a format specifier! */
{
char * sptr = specifier;
int wide_width = 0, short_width = 0;
*sptr++ = *ptr++; /* Copy the % and move forward. */
while (strchr ("-+ #0", *ptr)) /* Move past flags. */
*sptr++ = *ptr++;
if (*ptr == '*')
COPY_VA_INT;
else
while (ISDIGIT(*ptr)) /* Handle explicit numeric value. */
*sptr++ = *ptr++;
if (*ptr == '.')
{
*sptr++ = *ptr++; /* Copy and go past the period. */
if (*ptr == '*')
COPY_VA_INT;
else
while (ISDIGIT(*ptr)) /* Handle explicit numeric value. */
*sptr++ = *ptr++;
}
while (strchr ("hlL", *ptr))
{
switch (*ptr)
{
case 'h':
short_width = 1;
break;
case 'l':
wide_width++;
break;
case 'L':
wide_width = 2;
break;
default:
abort();
}
*sptr++ = *ptr++;
}
switch (*ptr)
{
case 'd':
case 'i':
case 'o':
case 'u':
case 'x':
case 'X':
case 'c':
{
/* Short values are promoted to int, so just copy it
as an int and trust the C library printf to cast it
to the right width. */
if (short_width)
PRINT_TYPE(int);
else
{
switch (wide_width)
{
case 0:
PRINT_TYPE(int);
break;
case 1:
PRINT_TYPE(long);
break;
case 2:
default:
#if defined(__GNUC__) || defined(HAVE_LONG_LONG)
PRINT_TYPE(long long);
#else
PRINT_TYPE(long); /* Fake it and hope for the best. */
#endif
break;
} /* End of switch (wide_width) */
} /* End of else statement */
} /* End of integer case */
break;
case 'f':
case 'e':
case 'E':
case 'g':
case 'G':
{
if (wide_width == 0)
PRINT_TYPE(double);
else
{
#if defined(__GNUC__) || defined(HAVE_LONG_DOUBLE)
PRINT_TYPE(long double);
#else
PRINT_TYPE(double); /* Fake it and hope for the best. */
#endif
}
}
break;
case 's':
PRINT_TYPE(char *);
break;
case 'p':
PRINT_TYPE(void *);
break;
case '%':
PRINT_CHAR('%');
break;
default:
abort();
} /* End of switch (*ptr) */
} /* End of else statement */
}
return total_printed;
}
#ifdef TEST
#include <math.h>;
#ifndef M_PI
#define M_PI (3.1415926535897932385)
#endif
#define RESULT(x) do \
{ \
int i = (x); \
printf ("printed %d characters\n", i); \
fflush(stdin); \
} while (0)
static int checkit PARAMS ((const char * format, ...)) ATTRIBUTE_PRINTF_1;
static int
checkit VPARAMS ((const char* format, ...))
{
int result;
VA_OPEN (args, format);
VA_FIXEDARG (args, char *, format);
result = _doprnt (format, args, stdout);
VA_CLOSE (args);
return result;
}
int
main ()
{
RESULT(checkit ("<%d>;\n", 0x1234567 );
RESULT(printf ("<%d>;\n", 0x1234567);
RESULT(checkit ("<%200d>;\n", 5));
RESULT(printf ("<%200d>;\n", 5));
RESULT(checkit ("<%.300d>;\n", 6));
RESULT(printf ("<%.300d>;\n", 6));
RESULT(checkit ("<%100.150d>;\n", 7));
RESULT(printf ("<%100.150d>;\n", 7));
RESULT(checkit ("<%s>;\n",
"jjjjjjjjjiiiiiiiiiiiiiiioooooooooooooooooppppppppppppaa\n\
777777777777777777333333333333366666666666622222222222777777777777733333" );
RESULT(printf ("<%s>;\n",
"jjjjjjjjjiiiiiiiiiiiiiiioooooooooooooooooppppppppppppaa\n\
777777777777777777333333333333366666666666622222222222777777777777733333");
RESULT(checkit ("<%f>;<%0+#f>;%s%d%s>;\n",
1.0, 1.0, "foo", 77, "asdjffffffffffffffiiiiiiiiiiixxxxx");
RESULT(printf ("<%f>;<%0+#f>;%s%d%s>;\n",
1.0, 1.0, "foo", 77, "asdjffffffffffffffiiiiiiiiiiixxxxx");
RESULT(checkit ("<%4f>;<%.4f>;<%%>;<%4.4f>;\n", M_PI, M_PI, M_PI));
RESULT(printf ("<%4f>;<%.4f>;<%%>;<%4.4f>;\n", M_PI, M_PI, M_PI));
RESULT(checkit ("<%*f>;<%.*f>;<%%>;<%*.*f>;\n", 3, M_PI, 3, M_PI, 3, 3, M_PI));
RESULT(printf ("<%*f>;<%.*f>;<%%>;<%*.*f>;\n", 3, M_PI, 3, M_PI, 3, 3, M_PI));
RESULT(checkit ("<%d>;<%i>;<%o>;<%u>;<%x>;<%X>;<%c>;\n",
75, 75, 75, 75, 75, 75, 75));
RESULT(printf ("<%d>;<%i>;<%o>;<%u>;<%x>;<%X>;<%c>;\n",
75, 75, 75, 75, 75, 75, 75));
RESULT(checkit ("<%d>;<%i>;<%o>;<%u>;<%x>;<%X>;<%c>;\n",
75, 75, 75, 75, 75, 75, 75));
RESULT(printf ("<%d>;<%i>;<%o>;<%u>;<%x>;<%X>;<%c>;\n",
75, 75, 75, 75, 75, 75, 75));
RESULT(checkit ("Testing (hd) short: <%d>;<%ld>;<%hd>;<%hd>;<%d>;\n", 123, (long)234, 345, 123456789, 456));
RESULT(printf ("Testing (hd) short: <%d>;<%ld>;<%hd>;<%hd>;<%d>;\n", 123, (long)234, 345, 123456789, 456));
#if defined(__GNUC__) || defined (HAVE_LONG_LONG)
RESULT(checkit ("Testing (lld) long long: <%d>;<%lld>;<%d>;\n", 123, 234234234234234234LL, 345));
RESULT(printf ("Testing (lld) long long: <%d>;<%lld>;<%d>;\n", 123, 234234234234234234LL, 345));
RESULT(checkit ("Testing (Ld) long long: <%d>;<%Ld>;<%d>;\n", 123, 234234234234234234LL, 345));
RESULT(printf ("Testing (Ld) long long: <%d>;<%Ld>;<%d>;\n", 123, 234234234234234234LL, 345));
#endif
#if defined(__GNUC__) || defined (HAVE_LONG_DOUBLE)
RESULT(checkit ("Testing (Lf) long double: <%.20f>;<%.20Lf>;<%0+#.20f>;\n",
1.23456, 1.234567890123456789L, 1.23456));
RESULT(printf ("Testing (Lf) long double: <%.20f>;<%.20Lf>;<%0+#.20f>;\n",
1.23456, 1.234567890123456789L, 1.23456));
#endif
return 0;
}
#endif /* TEST */ |
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楼主: partwithhook
发表于 2004-12-29 11:28
发表于 2004-12-29 11:32