PFValue Struct Reference

#include <pftypes.h>

List of all members.

Public Attributes
union {
long   i
	Union: Integer value.
float   f
	Union: Float value.
void *   p
	Union: Generic Pointer value.
}	value
PropertyType	type
	Value Type.
int	len
	length of array, if type is a buffer

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Detailed Description

Run time information data type.

This contains a value union and a type field

A PFValue is to be initialized as follows:

 v.type = <type>; v.value.<valuefield> = <value> 

For example, see macros SET_FLOAT, etc.

In case of a string or buffer value, it is important to know that the data buffer is not owned by the property structure, i.e. the PFValue only serves as a descriptor and no value copying actually happens. Therefore, the programmer has to distinguish between two cases before querying a property via pfDevice_GetProperty()

• The property is static (fixed length): The caller does not have to worry about pointer initialization of the PFValue before calling pfDevice_GetProperty()
• The property is dynamic (read/write) and the caller *must* initialize the value buffer.

For a dynamic string, the initialization would look as follows:

#define BUF_LEN 80
        PFValue v;
        char buffer[BUF_LEN];

        v.type = PF_STRING;
        v.len = BUF_LEN;
        v.value.p = buffer;

        pfDevice_GetProperty(d, property, &v);
        // ...
        //

Note that in this example, the (zero terminated) string has a maximum length of 79.

If there was not enough space reserved for the property buffer, an error PFERR_PROPERTY_SIZE_MATCH is returned from pfGetProperty()

Data type checking is performed when setting properties.

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The documentation for this struct was generated from the following file:

• pftypes.h