.\"	$NetBSD: prop_string.3,v 1.10 2020/06/06 21:25:59 thorpej Exp $
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.\" by Jason R. Thorpe.
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.Dd June 2, 2020
.Dt PROP_STRING 3
.Os
.Sh NAME
.Nm prop_string ,
.Nm prop_string_create_copy ,
.Nm prop_string_create_format ,
.Nm prop_string_create_nocopy ,
.Nm prop_string_value ,
.Nm prop_string_copy_value ,
.Nm prop_string_copy ,
.Nm prop_string_size ,
.Nm prop_string_equals ,
.Nm prop_string_equals_string ,
.Nm prop_string_compare ,
.Nm prop_string_compare_string
.Nd string value property object
.Sh LIBRARY
.Lb libprop
.Sh SYNOPSIS
.In prop/proplib.h
.\"
.Ft prop_string_t
.Fn prop_string_create_copy "const char *cstring"
.Ft prop_string_t
.Fn prop_string_create_format "const char *fmt" "..."
.Ft prop_string_t
.Fn prop_string_create_nocopy "const char *cstring"
.\"
.Ft prop_string_t
.Fn prop_string_copy "prop_string_t string"
.Ft bool
.Fn prop_string_copy_value "prop_string_t string" "char *buf" "size_t buflen"
.\"
.Ft size_t
.Fn prop_string_size "prop_string_t string"
.\"
.Ft const char *
.Fn prop_string_value "prop_string_t string"
.\"
.Ft bool
.Fn prop_string_equals "prop_string_t str1" "prop_string_t str2"
.Ft bool
.Fn prop_string_equals_string "prop_string_t string" "const char *cstring"
.\"
.Ft int
.Fn prop_string_compare "prop_string_t str1" "prop_string_t str2"
.Ft int
.Fn prop_string_compare_string "prop_string_t string" "const char *cstring"
.Sh DESCRIPTION
The
.Nm
family of functions operate on a string value property object type.
.Bl -tag -width "xxxxx"
.It Fn prop_string_create_copy "const char *cstring"
Create a string object that contains a copy of
.Fa cstring .
Returns
.Dv NULL
on failure.
.It Fn prop_string_create_format "const char *fmt" "..."
Similar to
.Fn prop_string_create_copy ,
but creates the string using the specified
.Xr printf 3
format.
.It Fn prop_string_create_nocopy "const char *cstring"
Similar to
.Fn prop_string_create_copy ,
but is allowed to not create an internal copy of the string data, instead
referencing the string data passed by the caller.
Caution must be exercised because string objects can have an indefinite
lifespan.
The caller must therefore ensure that the provided string data
reference will also be valid indefinitely.
This is provided only as a memory optimization; it is not guaranteed that
the returned string object will reference the provided string data, and
thus callers should not rely on this behavior.
Returns
.Dv NULL
on failure.
.It Fn prop_string_copy "prop_string_t string"
Copy a string object.
If the string object being copied has an external string buffer reference,
then the copy also references the same external string buffer.
Returns
.Dv NULL
on failure.
.It Fn prop_string_size "prop_string_t string"
Returns the size of the string, not including the terminating NUL;
equivalent semantics to
.Xr strlen 3 .
If the supplied object isn't a string, zero is returned.
.It Fn prop_string_value "prop_string_t string"
Returns an reference to the contents of the string as a C string.
If the supplied object isn't a string,
.Dv NULL
is returned.
.It Fn prop_string_copy_value "prop_string_t string" "void *buf" "size_t buflen"
Copies the contents of the string object including the terminating NUL
into the supplied buffer of the specified size.
Returns
.Dv true
if the copy succeeds
and
.Dv false
if the supplied buffer is not large enough or if the object is not a
string object.
.It Fn prop_string_equals "prop_string_t str1" "prop_string_t str2"
Returns
.Dv true
if the two string objects are equivalent.
.It Fn prop_string_equals_string "prop_string_t string" "const char *cstring"
Returns
.Dv true
if the string's value is equivalent to
.Fa cstring .
.It Fn prop_string_compare "prop_string_t str1" "prop_string_t str2"
Compares two strings using
.Xr strcmp 3
semantics.
If either of the two objects are not string objects, an arbitrary
non-matching value will be returned.
.It Fn prop_string_compare_string "prop_string_t string" "const char *cstring"
Compares the a string object to the specified C string using
.Xr strcmp 3
semantics.
If either the object is not a string object, an arbitrary
non-matching value will be returned.
.El
.Sh SEE ALSO
.Xr prop_array 3 ,
.Xr prop_bool 3 ,
.Xr prop_data 3 ,
.Xr prop_dictionary 3 ,
.Xr prop_number 3 ,
.Xr prop_object 3 ,
.Xr proplib 3
.Sh HISTORY
The
.Xr proplib 3
property container object library first appeared in
.Nx 4.0 .
Support for mutable string objects was deprecated in
.Nx 10.0 .