stdio-common/printf.h

   1 /* Copyright (C) 1991-2023 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    <https://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 #include <bits/types/FILE.h>
  26
  27 #define __need_size_t
  28 #define __need_wchar_t
  29 #include <stddef.h>
  30
  31 #include <stdarg.h>
  32
  33
  34 struct printf_info
  35 {
  36   int prec;                     /* Precision.  */
  37   int width;                    /* Width.  */
  38   wchar_t spec;                 /* Format letter.  */
  39   unsigned int is_long_double:1;/* L flag.  */
  40   unsigned int is_short:1;      /* h flag.  */
  41   unsigned int is_long:1;       /* l flag.  */
  42   unsigned int alt:1;           /* # flag.  */
  43   unsigned int space:1;         /* Space flag.  */
  44   unsigned int left:1;          /* - flag.  */
  45   unsigned int showsign:1;      /* + flag.  */
  46   unsigned int group:1;         /* ' flag.  */
  47   unsigned int extra:1;         /* For special use.  */
  48   unsigned int is_char:1;       /* hh flag.  */
  49   unsigned int wide:1;          /* Nonzero for wide character streams.  */
  50   unsigned int i18n:1;          /* I flag.  */
  51   unsigned int is_binary128:1;  /* Floating-point argument is ABI-compatible
  52                                    with IEC 60559 binary128.  */
  53   unsigned int __pad:3;         /* Unused so far.  */
  54   unsigned short int user;      /* Bits for user-installed modifiers.  */
  55   wchar_t pad;                  /* Padding character.  */
  56 };
  57
  58
  59 /* Type of a printf specifier-handler function.
  60    STREAM is the FILE on which to write output.
  61    INFO gives information about the format specification.
  62    ARGS is a vector of pointers to the argument data;
  63    the number of pointers will be the number returned
  64    by the associated arginfo function for the same INFO.
  65
  66    The function should return the number of characters written,
  67    or -1 for errors.  */
  68
  69 typedef int printf_function (FILE *__stream,
  70                              const struct printf_info *__info,
  71                              const void *const *__args);
  72
  73 /* Type of a printf specifier-arginfo function.
  74    INFO gives information about the format specification.
  75    N, ARGTYPES, *SIZE has to contain the size of the parameter for
  76    user-defined types, and return value are as for parse_printf_format
  77    except that -1 should be returned if the handler cannot handle
  78    this case.  This allows to partially overwrite the functionality
  79    of existing format specifiers.  */
  80
  81 typedef int printf_arginfo_size_function (const struct printf_info *__info,
  82                                           size_t __n, int *__argtypes,
  83                                           int *__size);
  84
  85 /* Old version of 'printf_arginfo_function' without a SIZE parameter.  */
  86
  87 typedef int printf_arginfo_function (const struct printf_info *__info,
  88                                      size_t __n, int *__argtypes);
  89
  90 /* Type of a function to get a value of a user-defined from the
  91    variable argument list.  */
  92 typedef void printf_va_arg_function (void *__mem, va_list *__ap);
  93
  94
  95 /* Register FUNC to be called to format SPEC specifiers; ARGINFO must be
  96    specified to determine how many arguments a SPEC conversion requires and
  97    what their types are.  */
  98
  99 extern int register_printf_specifier (int __spec, printf_function __func,
 100                                       printf_arginfo_size_function __arginfo)
 101   __THROW;
 102
 103
 104 /* Obsolete interface similar to register_printf_specifier.  It can only
 105    handle basic data types because the ARGINFO callback does not return
 106    information on the size of the user-defined type.  */
 107
 108 extern int register_printf_function (int __spec, printf_function __func,
 109                                      printf_arginfo_function __arginfo)
 110   __THROW __attribute_deprecated__;
 111
 112
 113 /* Register a new modifier character sequence.  If the call succeeds
 114    it returns a positive value representing the bit set in the USER
 115    field in 'struct printf_info'.  */
 116
 117 extern int register_printf_modifier (const wchar_t *__str) __THROW __wur;
 118
 119
 120 /* Register variable argument handler for user type.  The return value
 121    is to be used in ARGINFO functions to signal the use of the
 122    type.  */
 123 extern int register_printf_type (printf_va_arg_function __fct) __THROW __wur;
 124
 125
 126 /* Parse FMT, and fill in N elements of ARGTYPES with the
 127    types needed for the conversions FMT specifies.  Returns
 128    the number of arguments required by FMT.
 129
 130    The ARGINFO function registered with a user-defined format is passed a
 131    `struct printf_info' describing the format spec being parsed.  A width
 132    or precision of INT_MIN means a `*' was used to indicate that the
 133    width/precision will come from an arg.  The function should fill in the
 134    array it is passed with the types of the arguments it wants, and return
 135    the number of arguments it wants.  */
 136
 137 extern size_t parse_printf_format (const char *__restrict __fmt, size_t __n,
 138                                    int *__restrict __argtypes) __THROW;
 139
 140
 141 /* Codes returned by `parse_printf_format' for basic types.
 142
 143    These values cover all the standard format specifications.
 144    Users can reserve new values after PA_LAST for their own types
 145    using 'register_printf_type'.  */
 146
 147 enum
 148 {                               /* C type: */
 149   PA_INT,                       /* int */
 150   PA_CHAR,                      /* int, cast to char */
 151   PA_WCHAR,                     /* wide char */
 152   PA_STRING,                    /* const char *, a '\0'-terminated string */
 153   PA_WSTRING,                   /* const wchar_t *, wide character string */
 154   PA_POINTER,                   /* void * */
 155   PA_FLOAT,                     /* float */
 156   PA_DOUBLE,                    /* double */
 157   PA_LAST
 158 };
 159
 160 /* Flag bits that can be set in a type returned by `parse_printf_format'.  */
 161 #define PA_FLAG_MASK            0xff00
 162 #define PA_FLAG_LONG_LONG       (1 << 8)
 163 #define PA_FLAG_LONG_DOUBLE     PA_FLAG_LONG_LONG
 164 #define PA_FLAG_LONG            (1 << 9)
 165 #define PA_FLAG_SHORT           (1 << 10)
 166 #define PA_FLAG_PTR             (1 << 11)
 167
 168
 169
 170 /* Function which can be registered as `printf'-handlers.  */
 171
 172 /* Print floating point value using using abbreviations for the orders
 173    of magnitude used for numbers ('k' for kilo, 'm' for mega etc).  If
 174    the format specifier is a uppercase character powers of 1000 are
 175    used.  Otherwise powers of 1024.  */
 176 extern int printf_size (FILE *__restrict __fp,
 177                         const struct printf_info *__info,
 178                         const void *const *__restrict __args) __THROW;
 179
 180 /* This is the appropriate argument information function for `printf_size'.  */
 181 extern int printf_size_info (const struct printf_info *__restrict
 182                              __info, size_t __n, int *__restrict __argtypes)
 183      __THROW;
 184
 185 #include <bits/floatn.h>
 186 #if defined __LDBL_COMPAT || __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
 187 # include <bits/printf-ldbl.h>
 188 #endif
 189
 190 __END_DECLS
 191
 192 #endif /* printf.h  */