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| author | Joseph Myers <joseph@codesourcery.com> | 2023-06-19 19:40:34 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2023-06-19 19:40:34 +0000 |
| commit | 2d88df541132f09454d947c498103aa7be76b652 (patch) | |
| tree | 93e7cc592019cda92c8edb9a30ac4f1c2757386c /manual | |
| parent | 5f83b2674e42cd74257731b281f66d0442bf045f (diff) | |
| download | glibc-2d88df541132f09454d947c498103aa7be76b652.zip glibc-2d88df541132f09454d947c498103aa7be76b652.tar.gz glibc-2d88df541132f09454d947c498103aa7be76b652.tar.bz2 | |
C2x scanf %b support
ISO C2x defines scanf %b for input of binary integers (with an
optional 0b or 0B prefix). Implement such support, along with the
corresponding SCNb* macros in <inttypes.h>. Unlike the support for
binary integers with 0b or 0B prefix with scanf %i, this is supported
in all versions of scanf (independent of the standards mode used for
compilation), because there are no backwards compatibility concerns
(%b wasn't previously a supported format) the way there were for %i.
Tested for x86_64 and x86.
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/stdio.texi | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/manual/stdio.texi b/manual/stdio.texi index a981e65..9cf6224 100644 --- a/manual/stdio.texi +++ b/manual/stdio.texi @@ -3545,6 +3545,10 @@ Matches an optionally signed integer in any of the formats that the C language defines for specifying an integer constant. @xref{Numeric Input Conversions}. +@item @samp{%b} +Matches an unsigned integer written in binary radix. This is an ISO +C2X feature. @xref{Numeric Input Conversions}. + @item @samp{%o} Matches an unsigned integer written in octal radix. @xref{Numeric Input Conversions}. @@ -3652,11 +3656,13 @@ For example, any of the strings @samp{10}, @samp{0xa}, or @samp{012} could be read in as integers under the @samp{%i} conversion. Each of these specifies a number with decimal value @code{10}. -The @samp{%o}, @samp{%u}, and @samp{%x} conversions match unsigned -integers in octal, decimal, and hexadecimal radices, respectively. The +The @samp{%b}, @samp{%o}, @samp{%u}, and @samp{%x} conversions match unsigned +integers in binary, octal, decimal, and hexadecimal radices, respectively. The syntax that is recognized is the same as that for the @code{strtoul} function (@pxref{Parsing of Integers}) with the appropriate value -(@code{8}, @code{10}, or @code{16}) for the @var{base} argument. +(@code{2}, @code{8}, @code{10}, or @code{16}) for the @var{base} +argument. The @samp{%b} conversion accepts an optional leading +@samp{0b} or @samp{0B} in all standards modes. The @samp{%X} conversion is identical to the @samp{%x} conversion. They both permit either uppercase or lowercase letters to be used as digits. |