.Dd January 12, 2020
.Os libzt 0.3.1
.Dt ZT_NOT_NULL 3 PRM
.Sh NAME
.Nm ZT_NOT_NULL ,
.Nm zt_not_null
.Nd construct a claim that a pointer is not NULL
.Sh SYNOPSIS
.In zt.h
.Bd -literal
#define ZT_NOT_NULL(value) \\
  zt_not_null( \\
    ZT_CURRENT_LOCATION(), \\
    zt_pack_pointer((value), #value))
.Ed
.Ft zt_claim
.Fo zt_not_null
.Fa "zt_location location"
.Fa "zt_value value"
.Fc
.Sh DESCRIPTION
.Fn zt_not_null
constructs a claim that a given pointer is not NULL. It should be used through the
macro
.Fn ZT_NOT_NULL ,
which passes source code location and packs argument.
.Pp
.Fn ZT_NOT_NULL
can be useful, when coupled with
.Fn zt_assert ,
to ensure that an object was correctly produced, allocated or returned
and that the reminder of the test can inspect its properties using
.Fn zt_check .
.Sh IMPLEMENTATION NOTES
.Fn ZT_NOT_NULL
evaluates
.Em value
only once.
.Sh RETURN VALUES
Both the macro and the function return a
.Nm zt_claim
structure with the appropriate attributes set. The returned claim is usually
passed to
.Fn zt_check
or to
.Fn zt_assert .
.Sh SEE ALSO
.Xr zt_assert 3 ,
.Xr zt_check 3 ,
.Xr zt_claim 3 ,
.Xr ZT_CMP_BOOL 3 ,
.Xr ZT_CMP_RUNE 3 ,
.Xr ZT_CMP_CSTR 3 ,
.Xr ZT_CMP_INT 3 ,
.Xr ZT_CMP_PTR 3 ,
.Xr ZT_CMP_UINT 3 ,
.Xr ZT_FALSE 3 ,
.Xr ZT_NOT_NULL 3 ,
.Xr ZT_NOT_NULL 3
.Xr zt_value 3 ,
.Sh HISTORY
The
.Fn ZT_NOT_NULL
macro and the
.Fn zt_not_null
function first appeared in libzt 0.1
.Sh AUTHORS
.An "Zygmunt Krynicki" Aq Mt me@zygoon.pl