.TH "FBB::TypeTrait" "3bobcat" "2005\-2020" "libbobcat\-dev_5\&.07\&.00" "Error handler"

.PP 
.SH "NAME"
FBB::TypeTrait \- shortdesc
.PP 
.SH "SYNOPSIS"
\fB#include <bobcat/typetrait>\fP
.br 

.PP 
.SH "DESCRIPTION"

.PP 
\fBFBB::TypeTrait\fP is a traits class\&. It does not define any member
functions or data members, but merely types\&. It can be used to determine the
basic type and other characteristics of (const) plain, (const) pointer or
(const) reference types\&. It was designed after Alexandrescu\(cq\&s (2001)
\fITypeTraits\fP template class\&.
.PP 
The \fBFBB::LpromotesR\fP class template is used to determine, compile\-time,
whether its second (right\-hand side) template type can be promoted to its
first (left\-hand side) template type\&.
.PP 
The \fBFBB::Use\fP class template expects two typenames \fILHS\fP and \fIRHS\fP
and defines \fItypename Use<LHS, RHS>::type\fP as \fILHS\fP if \fIRHS\fP can be
promoted to \fILHS\fP or it defines \fItypename Use<LHS, RHS>::type\fP as \fIRHS\fP\&.
.PP 
.SH "NAMESPACE"
\fBFBB\fP
.br 
All constructors, members, operators and manipulators, mentioned in this
man\-page, are defined in the namespace \fBFBB\fP\&.
.PP 
.SH "INHERITS FROM"
\-
.PP 
.SH "TypeTrait<TYPE>"

.PP 
\fBTYPE\fP is the template type parameter whose characteristics must be
determined\&. 
.PP 
\fITypeTrait<TYPE>\fP defines the type \fIPlain\fP: the plain type (the type
without const, pointer, reference type indication) of any const or non\-const
plain, pointer, lvalue\- or rvalue\-reference type\&.
.PP 
\fITypeTrait<TYPE>\fP defines the following \fIbool\fP values:    
.IP o 
\fIisClass\fP: \fItrue\fP if the template type argument represents a
class (struct) type, \fIfalse\fP otherwise\&.
.IP o 
\fIisConst\fP: \fItrue\fP if the template type argument represents a
const type, \fIfalse\fP otherwise\&.
.IP o 
\fIisPointer\fP: \fItrue\fP if the template type argument represents a
pointer type, \fIfalse\fP otherwise\&.
.IP o 
\fIisR_Ref\fP: \fItrue\fP if the template type argument represents a
rvalue reference type, \fIfalse\fP otherwise\&.
.IP o 
\fIisRef\fP: \fItrue\fP if the template type argument represents an
lvalue reference type, \fIfalse\fP otherwise\&.

.PP 
.SH "LpromotesR<LeftType, RightType>"

.PP 
\fILpromotesR<LeftType, RightType>\fP defines the enum constant \fIyes\fP as 1
if an \fIRightType\fP argument can be promoted to \fILeftType\fP value or object\&.
The enum value \fIyes\fP is defined as 0 if no such constructor is available or if
such a constructor is defined using the \fIexplicit\fP keyword\&.
.PP 
.SH "EXAMPLES"

.PP 
Here is an example using \fILpromotesR\fP:
.nf 

    int main()
    {
        cout << \(dq\&string promotes char const *: \(dq\& << 
                LpromotesR<string, char const *>::yes << \(cq\&\en\(cq\&;  // 1
        cout << \(dq\&string promotes string \(dq\& << 
                LpromotesR<string, string>::yes << \(cq\&\en\(cq\&;        // 1
        cout << \(dq\&char const * promotes string \(dq\& << 
                LpromotesR<char const *, string>::yes << \(cq\&\en\(cq\&;  // 0
    }
        
.fi 

.PP 
.SH "FILES"
\fIbobcat/typetrait\fP \- defines the class interface
.PP 
.SH "SEE ALSO"
\fBbobcat\fP(7)
.br 
Alexandrescu A\&. (2001) \fBModern C++ Design\fP, Addison\-Wesley, Boston\&.
.PP 
.SH "BUGS"
None Reported\&.
.PP 
.SH "BOBCAT PROJECT FILES"

.PP 
.IP o 
\fIhttps://fbb\-git\&.gitlab\&.io/bobcat/\fP: gitlab project page;
.IP o 
\fIbobcat_5\&.07\&.00\-x\&.dsc\fP: detached signature;
.IP o 
\fIbobcat_5\&.07\&.00\-x\&.tar\&.gz\fP: source archive;
.IP o 
\fIbobcat_5\&.07\&.00\-x_i386\&.changes\fP: change log;
.IP o 
\fIlibbobcat1_5\&.07\&.00\-x_*\&.deb\fP: debian package containing the
libraries;
.IP o 
\fIlibbobcat1\-dev_5\&.07\&.00\-x_*\&.deb\fP: debian package containing the
libraries, headers and manual pages;

.PP 
.SH "BOBCAT"
Bobcat is an acronym of `Brokken\(cq\&s Own Base Classes And Templates\(cq\&\&.
.PP 
.SH "COPYRIGHT"
This is free software, distributed under the terms of the 
GNU General Public License (GPL)\&.
.PP 
.SH "AUTHOR"
Frank B\&. Brokken (\fBf\&.b\&.brokken@rug\&.nl\fP)\&.
.PP