.\"	$NetBSD: prop_number.3,v 1.9 2008/04/30 13:10:46 martin Exp $
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.\" by Jason R. Thorpe.
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.Dd January 21, 2008
.Dt PROP_NUMBER 3
.Os
.Sh NAME
.Nm prop_number ,
.Nm prop_number_create_integer ,
.Nm prop_number_create_unsigned_integer ,
.Nm prop_number_copy ,
.Nm prop_number_size ,
.Nm prop_number_unsigned ,
.Nm prop_number_integer_value ,
.Nm prop_number_unsigned_integer_value ,
.Nm prop_number_equals ,
.Nm prop_number_equals_integer ,
.Nm prop_number_equals_unsigned_integer
.Nd numeric value property object
.Sh LIBRARY
.Lb libprop
.Sh SYNOPSIS
.In libprop/proplib.h
.\"
.Ft prop_number_t
.Fn prop_number_create_integer "int64_t val"
.Ft prop_number_t
.Fn prop_number_create_unsigned_integer "uint64_t val"
.Ft prop_number_t
.Fn prop_number_copy "prop_number_t number"
.\"
.Ft int
.Fn prop_number_size "prop_number_t number"
.Ft bool
.Fn prop_number_unsigned "prop_number_t number"
.Ft int64_t
.Fn prop_number_integer_value "prop_number_t number"
.Ft uint64_t
.Fn prop_number_unsigned_integer_value "prop_number_t number"
.\"
.Ft bool
.Fn prop_number_equals "prop_number_t num1" "prop_number_t num2"
.Ft bool
.Fn prop_number_equals_integer "prop_number_t number" "int64_t val"
.Ft bool
.Fn prop_number_equals_unsigned_integer "prop_number_t number" "uint64_t val"
.Sh DESCRIPTION
The
.Nm prop_number
family of functions operate on a numeric value property object type.
Values are either signed or unsigned, and promoted to a 64-bit type
.Pq int64_t or uint64_t , respectively .
.Pp
It is possible to compare number objects that differ in sign.
Such comparisons first test to see if each object is within the valid
number range of the other:
.Bl -bullet
.It
Signed numbers that are greater than or equal to 0 can be compared to
unsigned numbers.
.It
Unsigned numbers that are less than or equal to the largest signed 64-bit
value
.Pq Dv INT64_MAX
can be compared to signed numbers.
.El
.Pp
Number objects have a different externalized representation depending
on their sign:
.Bl -bullet
.It
Signed numbers are externalized in base-10
.Pq decimal .
.It
Unsigned numbers are externalized in base-16
.Pq hexadecimal .
.El
.Pp
When numbers are internalized, the sign of the resulting number object
.Pq and thus its valid range
is determined by a set of rules evaluated in the following order:
.Bl -bullet
.It
If the first character of the number is a
.Sq -
then the number is signed.
.It
If the first two characters of the number are
.Sq 0x
then the number is unsigned.
.It
If the number value fits into the range of a signed number then the
number is signed.
.It
In all other cases, the number is unsigned.
.El
.Bl -tag -width "xxxxx"
.It Fn prop_number_create_integer "int64_t val"
Create a numeric value object with the signed value
.Fa val .
Returns
.Dv NULL
on failure.
.It Fn prop_number_create_unsigned_integer "uint64_t val"
Create a numeric value object with the unsigned value
.Fa val .
Returns
.Dv NULL
on failure.
.It Fn prop_number_copy "prop_number_t number"
Copy a numeric value object.
If the supplied object isn't a numeric value,
.Dv NULL
is returned.
.It Fn prop_number_size "prop_number_t number"
Returns 8, 16, 32, or 64, representing the number of bits required to
hold the value of the object.
If the supplied object isn't a numeric value,
.Dv NULL
is returned.
.It Fn prop_number_unsigned "prop_number_t number"
Returns
.Dv true
if the numeric value object has an unsigned value.
.It Fn prop_number_integer_value "prop_number_t number"
Returns the signed integer value of the numeric value object.
If the supplied object isn't a numeric value, zero is returned.
Thus,
it is not possible to distinguish between
.Dq not a prop_number_t
and
.Dq prop_number_t has a value of 0 .
.It Fn prop_number_unsigned_integer_value "prop_number_t number"
Returns the unsigned integer value of the numeric value object.
If the supplied object isn't a numeric value, zero is returned.
Thus,
it is not possible to distinguish between
.Dq not a prop_number_t
and
.Dq prop_number_t has a value of 0 .
.It Fn prop_number_equals "prop_number_t num1" "prop_number_t num2"
Returns
.Dv true
if the two numeric value objects are equivalent.
If at least one of the supplied objects isn't a numeric value,
.Dv false
is returned.
.It Fn prop_number_equals_integer "prop_number_t number" "int64_t val"
Returns
.Dv true
if the object's value is equivalent to the signed value
.Fa val .
If the supplied object isn't a numerical value or if
.Fa val
exceeds
.Dv INT64_MAX ,
.Dv false
is returned.
.It Fn prop_number_equals_unsigned_integer "prop_number_t number" \
    "uint64_t val"
Returns
.Dv true
if the object's value is equivalent to the unsigned value
.Fa val .
If the supplied object isn't a numerical value or if
.Fa val
exceeds
.Dv INT64_MAX ,
.Dv false
is returned.
.El
.Sh SEE ALSO
.Xr prop_array 3 ,
.Xr prop_bool 3 ,
.Xr prop_data 3 ,
.Xr prop_dictionary 3 ,
.Xr prop_object 3 ,
.Xr prop_string 3 ,
.Xr proplib 3
.Sh HISTORY
The
.Nm proplib
property container object library first appeared in
.Nx 4.0 .