Thread View: comp.std.c++
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Started by Shankar Unni
Thu, 09 Nov 1995 05:59
num_get<>::do_get() and field separators
Author: Shankar Unni
Date: Thu, 09 Nov 1995 05:59
Date: Thu, 09 Nov 1995 05:59
38 lines
2209 bytes
2209 bytes
I'm trying to implement bool input routines, and couldn't quite get a hang of
whether alphabetic bool input ("true", "false") must be followed by a
non-alphanumeric character or not. The latest draft says "reads characters
until it determines whether [ ... true or false sequence is present ... ]"..
I.e., given the following input:
truefalse
What is a call to
bool b;
num_get<char>::get(...., b, ..);
supposed to do? Is it supposed to consume "true", and return b == true with
the iterator pointing to 'f', or is it supposed to consume the entire token
and return a failure state without modifying b?
What about non-alphabetic bool input (i.e. reading 1 or 0)? Is that supposed
to be followed by a non-numeric character (looks like it)?
The quote from the Sep 95 draft is:
3 If flags.flag() & ios_base::boolalpha is false, num_get<>::get()
(_lib.category.numeric_) tries to read an integer value, which if
found must be 0 or 1; if the boolalpha flag is true, it reads charac
ters until it determines whether the numpunct<>::truename() or false
name() sequence23) is present. In either case if an exact match is
not found calls setstate(failbit).
--
Shankar Unni E-Mail: shankar@sgi.com
Silicon Graphics Inc. Phone: +1-415-933-2072
URL: http://reality.sgi.com/employees/shankar
---
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