PCML data tag

The PCML data tag can have the following attributes.

Attributes enclosed in brackets, [], indicate that the attribute is optional. If you specify an optional attribute, do not include the brackets in your source. Some attribute values are shown as a list of choices enclosed in braces, {}, with possible choices separated by vertical bars, |. When you specify one of these attributes, do not include the braces in your source and only specify one of the choices shown.

<data type="{ char | int | packed | zoned | float | byte | struct }"
    [ bidistringtype="{ ST4 | ST5 | ST6 | ST7 | ST8 | ST9 | ST10 | ST11 | DEFAULT }"]
    [ ccsid="{ number | data-name }" ]
    [ chartype="{ onebyte | twobyte }"]
    [ count="{ number | data-name }" ]
    [ init="string" ]
    [ length="{ number | data-name }" ]
    [ maxvrm="version-string" ]
    [ minvrm="version-string" ]
    [ name="name" ]
    [ offset="{ number | data-name }" ]
    [ offsetfrom="{ number | data-name | struct-name }" ]
    [ outputsize="{ number | data-name | struct-name }" ]
    [ passby= "{ reference | value }" ]
    [ precision="number" ]
    [ struct="struct-name" ]
    [ trim="{ right | left | both | none }" ]
    [ usage="{ inherit | input | output | inputoutput }" ]>
</data>

The following table lists the data tag attributes. Each entry includes the attribute name, the possible valid values, and a description of the attribute.

Attribute Value Description
type= char where char indicates a character value. A char data value is returned as a java.lang.String. For more information, see the char values for length.

int where int is an integer value. An int data value is returned as a java.lang.Long. For more information, see the int values for length and precision.

packed where packed is a packed decimal value. A packed data value is returned as a java.math.BigDecimal. For more information, see the packed values for length and precision.

zoned where zoned is a zoned decimal value. A zoned data value is returned as a java.math.BigDecimal. For more information, see the zoned values for length and precision.

float where float is a floating point value. The length attribute specifies the number of bytes, "4" or "8". A 4-byte integer is returned as a java.lang.Float. An 8-byte integer is returned as a java.lang.Double. For more information, see the float values for length.

byte where byte is a byte value. No conversion is performed on the data. A byte data value is returned as an array of byte values (byte[]). For more information, see the byte values for length.

struct where struct specifies the name of the <struct> element. A struct allows you to define a structure once and reuse it multiple times within the document. When you type="struct", it is as if the structure specified appeared at this location in the document. A struct does not allow for a length value and has no value for precision.

Indicates the type of data being used (character, integer, packed, zoned, floating point, byte, or struct).

Values for the length and precision attributes are different for different data types. For more information, see the Values for length and precision.

bidistringtype=

DEFAULT where DEFAULT is the default string type for non-bidirectional data (LTR).

ST4 where ST4 is String Type 4.

ST5 where ST5 is String Type 5.

ST6 where ST6 is String Type 6.

ST7 where ST7 is String Type 7.

ST8 where ST8 is String Type 8.

ST9 where ST9 is String Type 9.

ST10 where ST10 is String Type 10.

ST11 where ST11 is String Type 11.

Specifies the bidirectional string type for <data> elements with type="char". If this attribute is omitted, string type for this element is implied by the CCSID (whether explicitly specified or the default CCSID of the host environment).

String types are defined in the javadoc for the BidiStringType class.
ccsid= number where number defines a fixed, never-changing CCSID.

data-name where data-name defines the name that will contain, at runtime, the CCSID of the character data. The data-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference a <data> element that is defined with type="int". See Resolving Relative Names for more information on how relative names are resolved.

 Specifies the host Coded Character Set ID (CCSID) for character data for the <data> element. The ccsid attribute can be specified only for <data> elements with type="char".

If this attribute is omitted, character data for this element is assumed to be in the default CCSID of the host environment.
chartype=

onebyte where onebyte specifies the size of each character.

twobyte where twobyte specifies the size of each character.

When using chartype, the length="number" attribute specifies the number of characters, not the number of bytes.

 Specifies the size of each character.
count= number where number defines a fixed, never-changing number of elements in a sized array.

data-name where data-name defines the name of a <data> element within the PCML document that will contain, at runtime, the number of elements in the array. The data-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference a <data> element that is defined with type="int". See Resolving Relative Names for more information on how relative names are resolved.

 Specifies that the element is an array and identifies the number of entries in the array.

If the count attribute is omitted, the element is not defined as an array, although it may be contained within another element that is defined as an array.
init= string Specifies an initial value for the <data> element. The init value is used if an initial value is not explicitly set by the application program when <data> elements with usage="input" or usage="inputoutput" are used.

The initial value specified is used to initialize scalar values. If the element is defined as an array or is contained within a structure defined as an array, the initial value specified is used as an initial value for all entries in the array.
length= number where number defines the number of bytes that the data requires. However, when using the chartype attribute, number specifies the number of characters, not the number of bytes.

data-name where data-name defines the name of a <data> element within the PCML document that will contain, at runtime, the length. A data-name can be specified only for <data> elements with type="char" or type="byte". The data-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference a <data> element that is defined with type="int". See Resolving Relative Names for more information on how relative names are resolved.

 Specifies the length of the data element. Usage of this attribute varies depending on the data type. For more information, see the Values for length and precision.
maxvrm= version-string Specifies the highest version of iSeries™ on which this element exists. If the iSeries version is greater than the version specified on this attribute, this element and its children, if any exist, will not be processed during a call to a program. This attribute is helpful for defining program interfaces which differ between releases of iSeries.

The syntax of the version string must be "VvRrMm", where the capitals letters "V," "R," and "M" are literal characters and "v," "r," and "m" are one or more digits representing the version, release and modification level. The value for "v" must be from 1 to 255 inclusively. The value for "r" and "m" must be from 0 to 255, inclusively.
minvrm= version-string Specifies the lowest version of iSeries on which this element exists. If the iSeries version is less than the version specified on this attribute, this element and its children, if any exist, will not be processed during a call to a program. This attribute is helpful for defining program interfaces which differ between releases of iSeries.

The syntax of the version string must be "VvRrMm," where the capitals letters "V," "R," and "M" are literal characters and "v," "r," and "m" are one or more digits representing the version, release and modification level. The value for "v" must be from 1 to 255 inclusively. The value for "r" and "m" must be from 0 to 255, inclusively.
name= name Specifies the name of the <data> element.
offset= number where number defines a fixed, never-changing offset.

data-name where data-name defines the name of a <data> element within the PCML document that will contain, at runtime, the offset to this element. The data-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference a <data> element that is defined with type="int". See Resolving Relative Names for more information on how relative names are resolved.

 Specifies the offset to the <data> element within an output parameter.

Some programs return information with a fixed structure followed by one or more variable length fields or structures. In this case, the location of a variable length element is typically specified as an offset or displacement within the parameter.

An offset attribute is used in conjunction with the offsetfrom attribute. If the offsetfrom attribute is not specified, the base location for the offset specified on the offset attribute is the parent of this element. See Specifying Offsets for more information on how to use the offset and offsetfrom attributes.

The offset and offsetfrom attributes are only used to process output data from a program. These attributes do not control the offset or displacement of input data.

If this attribute is omitted, the location of the data for this element is immediately following the preceding element in the parameter, if any.
offsetfrom= number where number defines a fixed, never-changing base location. Number is most typically used to specify number="0" indicating that the offset is an absolute offset from the beginning of the parameter.

data-name where data-name defines the name of a <data> element used as a base location for the offset. The element name specified must be the parent or an ancestor of this element. The value from the offset attribute will be relative to the location of the element specified on this attribute. The data-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference an ancestor of this element. See Resolving Relative Names for more information on how relative names are resolved.

struct-name where struct-name defines the name of a <struct> element used as a base location for the offset. The element name specified must be the parent or an ancestor of this element. The value from the offset attribute will be relative to the location of the element specified on this attribute. The struct-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference an ancestor of this element. See Resolving Relative Names for more information on how relative names are resolved.

 Specifies the base location from which the offset attribute is relative.

If the offsetfrom attribute is not specified, the base location for the offset specified on the offset attribute is the parent of this element. See Specifying Offsets for more information on how to use the offset and offsetfrom attributes.

The offset and offsetfrom attributes are only used to process output data from a program. These attributes do not control the offset or displacement of input data.
outputsize= number where a number defines a fixed, never-changing number of bytes to reserve.

data-name where data-name defines the name of a <data> element within the PCML document that will contain, at runtime, the number of bytes to reserve for output data. The data-name specified can be a fully qualified name or a name that is relative to the current element. In either case, the name must reference a <data> element that is defined with type="int". See Resolving Relative Names for more information on how relative names are resolved.

 Specifies the number of bytes to reserve for output data for the element. For output parameters which are variable in length, the outputsize attribute is needed to specify how many bytes must be reserved for data to be returned from the iSeries program. An outputsize attribute can be specified on all variable length fields and variable sized arrays, or it can be specified for an entire parameter that contains one or more variable length fields.

Outputsize is not necessary and must not be specified for fixed-size output parameters.

The value specified on this attribute is used as the total size for the element including all the children of the element. Therefore, the outputsize attribute is ignored on any children or descendants of the element.

If outputsize is omitted, the number of bytes to reserve for output data is determined at runtime by adding the number of bytes to reserve for all of the children of the <struct> element.
passby= reference where reference indicates that the parameter will be passed by reference. When the program is called, the program will be passed a pointer to the parameter value.

value where value indicates an integer value. This value is allowed only when type= "int" and length="4" is specified.

 Specifies whether the parameter is passed by reference or passed by value. This attribute is allowed only when this element is a child of a <program> element defining a service program call.
precision= number Specifies the number of bytes of precision for some numeric data types. For more information, see the Values for length and precision.
struct= name Specifies the name of a <struct> element for the <data> element. A struct attribute can be specified only for <data> elements with type="struct".
trim=

right where right is the default behavior that means to trim trailing white spaces.

left where left means to trim preceding white spaces.

both where both means to trim both preceding and trailing white spaces.

none where none means that white spaces are not trimmed.

 Specifies how to trim white space from character data.
usage= inherit Usage is inherited from the parent element. If the structure does not have a parent, usage is assumed to be inputoutput.
input Defines an input value to the host program. For character and numeric types, the appropriate conversion is performed.
output Defines an output value from the host program. For character and numeric types, the appropriate conversion is performed.
inputoutput Defines both and input and an output value.

Specifying offsets

Some programs return information with a fixed structure followed by one or more variable length fields or structures. In this case, the location of a variable length element is typically specified as an offset or displacement within the parameter.

An offset is the distance in bytes from the beginning of the parameters to the beginnings of a field or structure. A displacement is the distance in bytes from the beginning of one structure to the beginning of another structure.

For offsets, since the distance is from the beginning of the parameter, you must specify offsetfrom="0". The following is an example of an offset from the beginning of the parameter:

<pcml version="1.0">
  <program name="myprog" path="/QSYS.lib/MYLIB.lib/MYPROG.pgm">
    <!-- receiver variable contains a path -->
    <struct name="receiver" usage="output" outputsize="2048">
      <data name="pathType"         type="int"  length="4" />
      <data name="offsetToPathName" type="int"  length="4" />
      <data name="lengthOfPathName" type="int"  length="4" />
      <data name="pathName"         type="char" length="lengthOfPathName" 
               offset="offsetToPathName"  offsetfrom="0"/>
    </struct>
  </program>
</pcml>

For displacements, since the distance is from the beginning of another structure, you specify the name of the structure to which the offset is relative. The following is an example of an displacement from the beginning of a named structure:

<pcml version="1.0">
  <program name="myprog" path="/QSYS.lib/MYLIB.lib/MYPROG.pgm">
    <!-- receiver variable contains an object -->
    <struct name="receiver" usage="output" >
      <data name="objectName"       type="char"  length="10" />
      <data name="libraryName"      type="char"  length="10" />
      <data name="objectType"       type="char"  length="10" />
      <struct name="pathInfo" usage="output" outputsize="2048" >
        <data name="pathType"         type="int"  length="4" />
        <data name="offsetToPathName" type="int"  length="4" />
        <data name="lengthOfPathName" type="int"  length="4" />
        <data name="pathName"         type="char" length="lengthOfPathName" 
                 offset="offsetToPathName"  offsetfrom="pathInfo"/>
      </struct>
    </struct>
  </program>
</pcml>
Parent topic: PCML syntax