stdio-common/printf.h

   1 /* Copyright (C) 1991-2016 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifndef _PRINTF_H
  19
  20 #define _PRINTF_H       1
  21 #include <features.h>
  22
  23 __BEGIN_DECLS
  24
  25 #define __need_FILE
  26 #include <stdio.h>
  27 #define __need_size_t
  28 #define __need_wchar_t
  29 #include <stddef.h>
  30 #include <stdarg.h>
  31
  32
  33 struct printf_info
  34 {
  35   int prec;                     /* Precision.  */
  36   int width;                    /* Width.  */
  37   wchar_t spec;                 /* Format letter.  */
  38   unsigned int is_long_double:1;/* L flag.  */
  39   unsigned int is_short:1;      /* h flag.  */
  40   unsigned int is_long:1;       /* l flag.  */
  41   unsigned int alt:1;           /* # flag.  */
  42   unsigned int space:1;         /* Space flag.  */
  43   unsigned int left:1;          /* - flag.  */
  44   unsigned int showsign:1;      /* + flag.  */
  45   unsigned int group:1;         /* ' flag.  */
  46   unsigned int extra:1;         /* For special use.  */
  47   unsigned int is_char:1;       /* hh flag.  */
  48   unsigned int wide:1;          /* Nonzero for wide character streams.  */
  49   unsigned int i18n:1;          /* I flag.  */
  50   unsigned int __pad:4;         /* Unused so far.  */
  51   unsigned short int user;      /* Bits for user-installed modifiers.  */
  52   wchar_t pad;                  /* Padding character.  */
  53 };
  54
  55
  56 /* Type of a printf specifier-handler function.
  57    STREAM is the FILE on which to write output.
  58    INFO gives information about the format specification.
  59    ARGS is a vector of pointers to the argument data;
  60    the number of pointers will be the number returned
  61    by the associated arginfo function for the same INFO.
  62
  63    The function should return the number of characters written,
  64    or -1 for errors.  */
  65
  66 typedef int printf_function (FILE *__stream,
  67                              const struct printf_info *__info,
  68                              const void *const *__args);
  69
  70 /* Type of a printf specifier-arginfo function.
  71    INFO gives information about the format specification.
  72    N, ARGTYPES, *SIZE has to contain the size of the parameter for
  73    user-defined types, and return value are as for parse_printf_format
  74    except that -1 should be returned if the handler cannot handle
  75    this case.  This allows to partially overwrite the functionality
  76    of existing format specifiers.  */
  77
  78 typedef int printf_arginfo_size_function (const struct printf_info *__info,
  79                                           size_t __n, int *__argtypes,
  80                                           int *__size);
  81
  82 /* Old version of 'printf_arginfo_function' without a SIZE parameter.  */
  83
  84 typedef int printf_arginfo_function (const struct printf_info *__info,
  85                                      size_t __n, int *__argtypes);
  86
  87 /* Type of a function to get a value of a user-defined from the
  88    variable argument list.  */
  89 typedef void printf_va_arg_function (void *__mem, va_list *__ap);
  90
  91
  92 /* Register FUNC to be called to format SPEC specifiers; ARGINFO must be
  93    specified to determine how many arguments a SPEC conversion requires and
  94    what their types are.  */
  95
  96 extern int register_printf_specifier (int __spec, printf_function __func,
  97                                       printf_arginfo_size_function __arginfo)
  98   __THROW;
  99
 100
 101 /* Obsolete interface similar to register_printf_specifier.  It can only
 102    handle basic data types because the ARGINFO callback does not return
 103    information on the size of the user-defined type.  */
 104
 105 extern int register_printf_function (int __spec, printf_function __func,
 106                                      printf_arginfo_function __arginfo)
 107   __THROW __attribute_deprecated__;
 108
 109
 110 /* Register a new modifier character sequence.  If the call succeeds
 111    it returns a positive value representing the bit set in the USER
 112    field in 'struct printf_info'.  */
 113
 114 extern int register_printf_modifier (const wchar_t *__str) __wur __THROW;
 115
 116
 117 /* Register variable argument handler for user type.  The return value
 118    is to be used in ARGINFO functions to signal the use of the
 119    type.  */
 120 extern int register_printf_type (printf_va_arg_function __fct) __wur __THROW;
 121
 122
 123 /* Parse FMT, and fill in N elements of ARGTYPES with the
 124    types needed for the conversions FMT specifies.  Returns
 125    the number of arguments required by FMT.
 126
 127    The ARGINFO function registered with a user-defined format is passed a
 128    `struct printf_info' describing the format spec being parsed.  A width
 129    or precision of INT_MIN means a `*' was used to indicate that the
 130    width/precision will come from an arg.  The function should fill in the
 131    array it is passed with the types of the arguments it wants, and return
 132    the number of arguments it wants.  */
 133
 134 extern size_t parse_printf_format (const char *__restrict __fmt, size_t __n,
 135                                    int *__restrict __argtypes) __THROW;
 136
 137
 138 /* Codes returned by `parse_printf_format' for basic types.
 139
 140    These values cover all the standard format specifications.
 141    Users can reserve new values after PA_LAST for their own types
 142    using 'register_printf_type'.  */
 143
 144 enum
 145 {                               /* C type: */
 146   PA_INT,                       /* int */
 147   PA_CHAR,                      /* int, cast to char */
 148   PA_WCHAR,                     /* wide char */
 149   PA_STRING,                    /* const char *, a '\0'-terminated string */
 150   PA_WSTRING,                   /* const wchar_t *, wide character string */
 151   PA_POINTER,                   /* void * */
 152   PA_FLOAT,                     /* float */
 153   PA_DOUBLE,                    /* double */
 154   PA_LAST
 155 };
 156
 157 /* Flag bits that can be set in a type returned by `parse_printf_format'.  */
 158 #define PA_FLAG_MASK            0xff00
 159 #define PA_FLAG_LONG_LONG       (1 << 8)
 160 #define PA_FLAG_LONG_DOUBLE     PA_FLAG_LONG_LONG
 161 #define PA_FLAG_LONG            (1 << 9)
 162 #define PA_FLAG_SHORT           (1 << 10)
 163 #define PA_FLAG_PTR             (1 << 11)
 164
 165
 166
 167 /* Function which can be registered as `printf'-handlers.  */
 168
 169 /* Print floating point value using using abbreviations for the orders
 170    of magnitude used for numbers ('k' for kilo, 'm' for mega etc).  If
 171    the format specifier is a uppercase character powers of 1000 are
 172    used.  Otherwise powers of 1024.  */
 173 extern int printf_size (FILE *__restrict __fp,
 174                         const struct printf_info *__info,
 175                         const void *const *__restrict __args) __THROW;
 176
 177 /* This is the appropriate argument information function for `printf_size'.  */
 178 extern int printf_size_info (const struct printf_info *__restrict
 179                              __info, size_t __n, int *__restrict __argtypes)
 180      __THROW;
 181
 182 #ifdef __LDBL_COMPAT
 183 # include <bits/printf-ldbl.h>
 184 #endif
 185
 186 __END_DECLS
 187
 188 #endif /* printf.h  */