1XDF_CLOSEST_TYPE(3)        xdffileio library manual        XDF_CLOSEST_TYPE(3)
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NAME

6       xdf_closest_type - Returns a compatible data type
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SYNOPSIS

9       #include <xdfio.h>
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11       int xdf_closest_type(struct xdf* xdf, enum xdftype target);
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DESCRIPTION

14       xdf_closest_type()  selects  among the data types supported by the file
15       referenced by xdf the type that is the closest to the target  argument.
16       The   selected   type   can   then   be   safely  used  in  a  call  to
17       xdf_set_chconf(3) with the XDF_CF_STOTYPE field.
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19       The selection algorithm is based on the 3 following  criterions  (cited
20       by   priority,   i.e.   most   important   cited   first):  data  size,
21       signed/unsigned type, float/integer  value.  The  data  size  criterion
22       forces  the selected type to have a data size (number of byte to repre‐
23       sent the value) equal or bigger than the one of the target type (with a
24       preference  with  sizes  the  closest  to  the  size  of  target).  The
25       signed/unsigned criterion tries to select a  type  that  has  the  same
26       signeness  (signed  or  unsigned  data type) as the target. Finally the
27       float/integer criterion tries to select a floating point type if target
28       is  float  or  double  or  an integer data type if target is an integer
29       type.
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31       As a consequence, if target is supported by the underlying file  format
32       of xdf, the function is ensured to return target.
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RETURN VALUE

35       xdf_closest_type()  returns  the selected data type in case of success,
36       otherwise -1 and errno is set appropriately.
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ERRORS

39       EINVAL the xdf pointer is NULL, or the argument type is not an admissi‐
40              ble enum xdftype value.
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SEE ALSO

43       xdf_set_chconf(3)
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50EPFL                                 2010                  XDF_CLOSEST_TYPE(3)
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