.\"Copyright 2010 (c) EPFL
.TH XDF_CLOSEST_TYPE 3 2010 "EPFL" "xdffileio library manual"
.SH NAME
xdf_closest_type - Returns a compatible data type
.SH SYNOPSIS
.LP
.B #include <xdfio.h>
.sp
.BI "int xdf_closest_type(struct xdf* " xdf ", enum xdftype " target ");"
.br
.SH DESCRIPTION
.LP
\fBxdf_closest_type\fP() selects among the data types supported by the file
referenced by \fIxdf\fP the type that is the closest to the \fItarget\fP
argument. The selected type can then be safely used in a call to
\fBxdf_set_chconf\fP(3) with the \fBXDF_CF_STOTYPE\fP field.
.LP
The selection algorithm is based on the 3 following criterions (cited by
priority, i.e. most important cited first): data size, signed/unsigned type,
float/integer value. The data size criterion forces the selected type to
have a data size (number of byte to represent the value) equal or bigger
than the one of the target type (with a preference with sizes the closest to
the size of \fItarget\fP). The signed/unsigned criterion tries to
select a type that has the same signeness (signed or unsigned data type) as
the target. Finally the float/integer criterion tries to select a floating
point type if \fItarget\fP is float or double or an integer data type if
\fItarget\fP is an integer type.
.LP
As a consequence, if \fItarget\fP is supported by the underlying file format
of \fIxdf\fP, the function is ensured to return \fItarget\fP.
.SH "RETURN VALUE"
.LP
\fBxdf_closest_type\fP() returns the selected data type in case of success,
otherwise \-1 and \fIerrno\fP is set appropriately.
.SH ERRORS
.TP 7
.B EINVAL
the \fIxdf\fP pointer is \fBNULL\fP, or the argument \fItype\fP is not
an admissible \fBenum xdftype\fP value.
.SH "SEE ALSO"
.BR xdf_set_chconf (3)