Q:

Programming IBM iSeries API QUSLSPL in C#

Can somebody help me with the complete c# code to call QUSLSPL with SPLF0200 format.  I am able to call the program but don't know how to capture/read through the output.  I am new to this area.  Appreciate your help. 
Here is my code. 
cwbx. ProgramParameters parameters = new cwbx. ProgramParameters();

        //user space name
        parameters. Append("usrspcnam", cwbrcParameterTypeEnum.cwbrcInout, 20);
        StringConverter stringConverterUsrSpaceNm = new cwbx. StringConverter();
        stringConverterUsrSpaceNm. Length = 20;
        parameters["usrspcnam"].Value = stringConverterUsrSpaceNm. ToBytes("HRAHMAN   QGPL      ");

        //Format
        parameters. Append("frmname", cwbrcParameterTypeEnum.cwbrcInout, 8);
        StringConverter stringConverterFrmname = new cwbx. StringConverter();
        stringConverterFrmname. Length = 8;
        parameters["frmname"].Value = stringConverterFrmname. ToBytes("SPLF0200");

        //User Name
        parameters. Append("usrnam", cwbrcParameterTypeEnum.cwbrcInout, 10);
        StringConverter stringConverterUsrnam = new cwbx. StringConverter();
        stringConverterUsrnam. Length = 10;
        //parameters["usrnam"].Value = stringConverterUsrnam. ToBytes("*CURRENT");
        parameters["usrnam"].Value = stringConverterUsrnam. ToBytes("          ");

        //qualified output queue
        parameters. Append("cola", cwbrcParameterTypeEnum.cwbrcInout, 20);
        StringConverter stringConverterCola = new cwbx. StringConverter();
        stringConverterCola. Length = 20;
        //parameters["cola"].Value = stringConverterCola. ToBytes("*ALL");
        parameters["cola"].Value = stringConverterCola. ToBytes("                    ");

        //form type
        parameters. Append("frmtyp", cwbrcParameterTypeEnum.cwbrcInout, 10);
        StringConverter stringConverterFrmtyp = new cwbx. StringConverter();
        stringConverterFrmtyp. Length = 10;
        //parameters["frmtyp"].Value = stringConverterFrmtyp. ToBytes("*ALL");
        parameters["frmtyp"].Value = stringConverterFrmtyp. ToBytes("          ");

        //user-specific data
        parameters. Append("usrdta", cwbrcParameterTypeEnum.cwbrcInout, 10);
        StringConverter stringConverterUsrdta = new cwbx. StringConverter();
        stringConverterUsrdta. Length = 10;
        //parameters["usrdta"].Value = stringConverterUsrdta. ToBytes("*ALL");
        parameters["usrdta"].Value = stringConverterUsrdta. ToBytes("          ");

//error
        parameters. Append("error", cwbrcParameterTypeEnum.cwbrcInout, 116);
        Structure sc2 = new Structure();
        sc2.Fields. Append("bytesprov", 4);
        sc2.Fields. Append("bytesavail", 4);
        sc2.Fields. Append("messageid", 7);
        sc2.Fields. Append("err", 1);
        sc2.Fields. Append("messagedta", 100);
        parameters["error"].Value = sc2.Bytes;

        //qualified job name
        parameters. Append("qualifiedjobnm", cwbrcParameterTypeEnum.cwbrcInput, 26);
        StringConverter stringConverterUsrdta1 = new cwbx. StringConverter();
        stringConverterUsrdta1.Length = 26;
        parameters["qualifiedjobnm"].Value = stringConverterUsrdta1.ToBytes("*                         ");

        //keys
        parameters. Append("keys", cwbrcParameterTypeEnum.cwbrcInput, 44); //44 is 11 keys times 4 bytes per key
        LongConverter lc = new cwbx. LongConverter();

        Structure keys = new Structure();
        keys. Fields. Append("Spooledfilename", 4); //char10 201
        keys. Fields["Spooledfilename"].Value = lc. ToBytes(201);
        keys. Fields. Append("Username", 4); //char10 203
        keys. Fields["Username"].Value = lc. ToBytes(203);
        keys. Fields. Append("opqueue", 4); //206
        keys. Fields["opqueue"].Value = lc. ToBytes(206);
        keys. Fields. Append("userdata", 4); //209
        keys. Fields["userdata"].Value = lc. ToBytes(209);
        keys. Fields. Append("status", 4); //210
        keys. Fields["status"].Value = lc. ToBytes(210);
        keys. Fields. Append("totpages", 4); //bin 211
        keys. Fields["totpages"].Value = lc. ToBytes(211);
        keys. Fields. Append("copies", 4); //bin 213
        keys. Fields["copies"].Value = lc. ToBytes(213);
        keys. Fields. Append("openeddate", 4); //216
        keys. Fields["openeddate"].Value = lc. ToBytes(216);
        keys. Fields. Append("opentime", 4); //217
        keys. Fields["opentime"].Value = lc. ToBytes(217);
        keys. Fields. Append("jobid", 4); //218
        keys. Fields["jobid"].Value = lc. ToBytes(218);
        keys. Fields. Append("fileid", 4); //219
        keys. Fields["fileid"].Value = lc. ToBytes(219);
        parameters["keys"].Value = keys. Bytes;

        //number of keys to return
        parameters. Append("numberoffields", cwbrcParameterTypeEnum.cwbrcInput, 4);
        LongConverter LongConverterKeys = new cwbx. LongConverter();
        parameters["numberoffields"].Value = LongConverterKeys. ToBytes(11); //11 keys in total

        program. Invoke(true, ref parameters);

Now what next?  Where and how to read output?  Appreciate your response. 

A:

You picked a humdinger of an API to start out with.   You have a user space list API with an all-key list format.   Those are complex.   I'll do my best to explain it all.   Buckle up! 
The QUSLSPL API does not return anything except what's in the error structure.   Everything else is an input parameter.   To access the spooled file list generated by the API, you must access the user space object.   In your example, the user space is QGPL/HRAHMAN.   Before I get into examining the output of the user space, let's get into understanding how to use a user space. 
What is a user space? 
A user space is just a big old block of bytes stored in a library on the host system with a maximum size of 16,776,704 bytes.   You can use them for more than just list API results, but that's all I really use them for.   The steps for list APIs that require user spaces are as such:

Create user space. 
Call the API. 
Check for errors from the API. 
Find the size of each entry. 
Find the start of the list data. 
Loop through the entries in the user space. 
Delete the user space. 

Create the user space
Creating the user space is done via the Create User Space (QUSCRTUS) API.   This API is pretty straight-forward.   You pass it a qualified name of the user space, some initial values, and the API error structure (so you can handle problems that come up).   The API definition can be found here: http://www.ibm.com/support/knowledgecenter/ssw_ibm_i_71/apis/quscrtus.htm
The parameters are:

Fully qualified name (char[20])
Extended Attribute (char[10])
Initial Size (binary[4])
Initial Value (char[1])
Public Authority (char[10])
Text Description (char[50])
Replace (char[10])
API Error Structure

Retrieve data from the user space
After you call the QUSLSPL API, you need to retrieve the data from the user space.   For that you use the QUSRTVUS API.   This API takes the user space name, the starting position, length, receiver variable, and the API error structure.   The API definition is here: http://www.ibm.com/support/knowledgecenter/ssw_ibm_i_71/apis/qusrtvus.htm
The parameters are:

Fully Qualified name (char[20])
Starting Position (binary[4]) Note: this is 1-based, not zero-based. 
Length of data to return (binary[4])
Receiver variable (*)
API Error Structure

Delete the user space
When you're all done, delete the user space using the QUSDLTUS API.   This one is even easier, it takes the fully qualified name and the API error structure.  The API definition is found here: http://www.ibm.com/support/knowledgecenter/ssw_ibm_i_71/apis/qusdltus.htm
List API Structure in the User Space
List APIs return data to the user space in a specific format.   It looks like this:

A user area
A generic header
An input parameter section
A header section
A list data section

What really matters, as far as reading through a list API are the following values in the front of the user space, in that generic header.   Note that these positions are zero-based. 

Position 0x7c: Offset to the list data section
Position 0x84: Number of list entries
Position 0x88: Size of each entry

With this information, you read the user space in chunks.   Each chunk starts at offset+(current zero-based entry number * size of each entry) and runs for the length of the entry size. 
Looking at the results from QUSLSPL
Each entry in the list returned from QUSLSPL for format SPLF0200 has two parts.   The first 4 bytes hold a count of fields returned.   Then it has the field data structure repeated for each field.   The size of the field data structure is variable.   You have to loop through it for each field, look at the field key, and use that determine which value got returned.   The end result is a two-level loop.  The outer loop cycles through each spooled file entry.   The inner loop cycles through each field returned in the SPLF0200 format. 
Here is some sample code, based on your original question.   Some notes, first:

I did not put in error checking or try/catch logic around the API calls, but a production program would have that. 
I would probably put the user space API calls into their own class for reusability. 
I changed how you set your input parameter values to be more streamlined. 
I use a single StringConverter and LongConverter for all conversions. 

Also note that I altered the parameters slightly to bring up the current user's spooled files because, in testing this sample, I didn't want to have to generate spooled data within the current job. 
//Define a single StringConverter and LongConverter to re-use
cwbx. StringConverter stringConverter = new cwbx. StringConverter();
cwbx. LongConverter longConverter = new cwbx. LongConverter();

//Type the user space name only once.   It's re-used a lot. 
String userSpaceName = "HRAHMAN   QGPL      ";

//Connect to the AS/400
AS400System as400 = new AS400System();
as400.Define("MY_SYSTEM_HOST_ADDRESS");
as400.UserID = "MY_USER";
as400.Password = "MY_PASSWORD";
as400.Connect(cwbcoServiceEnum.cwbcoServiceRemoteCmd);

//Define the error structure once, to be re-used a lot. 
Structure sc2 = new Structure();
sc2.Fields. Append("bytesprov", 4);
sc2.Fields. Append("bytesavail", 4);
sc2.Fields. Append("messageid", 7);
sc2.Fields. Append("err", 1);
sc2.Fields. Append("messagedta", 100);
sc2.Fields["bytesavail"].Value = longConverter. ToBytes(sc2.Length);

//Create the user space
cwbx. Program quscrtus = new cwbx. Program();
quscrtus.system = as400;
quscrtus. LibraryName = "QSYS";
quscrtus. ProgramName = "QUSCRTUS";

cwbx. ProgramParameters quscrtusParms = new cwbx. ProgramParameters();
quscrtusParms. Append("UserSpaceName", cwbrcParameterTypeEnum.cwbrcInput, 20).Value = stringConverter. ToBytes(userSpaceName);
quscrtusParms. Append("ExtendedAttr", cwbrcParameterTypeEnum.cwbrcInput, 10).Value = stringConverter. ToBytes("". PadRight(10));
quscrtusParms. Append("InitialSize", cwbrcParameterTypeEnum.cwbrcInput, 4).Value = longConverter. ToBytes(1);
quscrtusParms. Append("InitialValue", cwbrcParameterTypeEnum.cwbrcInput, 1).Value = longConverter. ToBytes(0);
quscrtusParms. Append("Auth", cwbrcParameterTypeEnum.cwbrcInput, 10).Value = stringConverter. ToBytes("*ALL". PadRight(10));
quscrtusParms. Append("Desc", cwbrcParameterTypeEnum.cwbrcInput, 50).Value = stringConverter. ToBytes("QUSLSPL Results". PadRight(50));
quscrtusParms. Append("Replace", cwbrcParameterTypeEnum.cwbrcInput, 10).Value = stringConverter. ToBytes("*YES". PadRight(10));
quscrtusParms. Append("APIError", cwbrcParameterTypeEnum.cwbrcInout, sc2.Length).Value = sc2.Bytes;
quscrtus. Call(quscrtusParms);
sc2.Bytes = quscrtusParms["APIError"].Value;
if (((string)stringConverter. FromBytes(sc2.Fields["messageid"].Value)).Trim().Length > 0)
{
    //deal with error
    return;
}

//Call the list spooled files API
cwbx. Program quslspl = new cwbx. Program();
quslspl.system = as400;
quslspl. LibraryName = "QSYS";
quslspl. ProgramName = "QUSLSPL";

ProgramParameters quslsplParms = new cwbx. ProgramParameters();
quslsplParms. Append("usrspcnam", cwbrcParameterTypeEnum.cwbrcInput, 20).Value = stringConverter. ToBytes(userSpaceName); //user space name
quslsplParms. Append("frmname", cwbrcParameterTypeEnum.cwbrcInput, 8).Value = stringConverter. ToBytes("SPLF0200"); //Format
quslsplParms. Append("usrnam", cwbrcParameterTypeEnum.cwbrcInput, 10).Value = stringConverter. ToBytes("*CURRENT". PadRight(10)); //User Name
quslsplParms. Append("cola", cwbrcParameterTypeEnum.cwbrcInput, 20).Value = stringConverter. ToBytes("*ALL". PadRight(20)); //qualified output queue
quslsplParms. Append("frmtyp", cwbrcParameterTypeEnum.cwbrcInput, 10).Value = stringConverter. ToBytes("*ALL". PadRight(10)); //form type
quslsplParms. Append("usrdta", cwbrcParameterTypeEnum.cwbrcInput, 10).Value = stringConverter. ToBytes("*ALL". PadRight(10)); //user-specific data
quslsplParms. Append("error", cwbrcParameterTypeEnum.cwbrcInout, sc2.Length).Value = sc2.Bytes; //error
quslsplParms. Append("qualifiedjobnm", cwbrcParameterTypeEnum.cwbrcInput, 26).Value = stringConverter. ToBytes("". PadRight(26)); //qualified job name

//keys.  The SPLF0200 structure uses a list of field keys.   So we tell the API which keys we want and that's what it returns. 
cwbx. Structure keys = new cwbx. Structure();
keys. Fields. Append("Spooledfilename", 4).Value = longConverter. ToBytes(201);
keys. Fields. Append("Username", 4).Value = longConverter. ToBytes(203);
keys. Fields. Append("opqueue", 4).Value = longConverter. ToBytes(206);
keys. Fields. Append("userdata", 4).Value = longConverter. ToBytes(209);
keys. Fields. Append("status", 4).Value = longConverter. ToBytes(210);
keys. Fields. Append("totpages", 4).Value = longConverter. ToBytes(211);
keys. Fields. Append("copies", 4).Value = longConverter. ToBytes(213);
keys. Fields. Append("openeddate", 4).Value = longConverter. ToBytes(216);
keys. Fields. Append("opentime", 4).Value = longConverter. ToBytes(217);
keys. Fields. Append("jobid", 4).Value = longConverter. ToBytes(218);
keys. Fields. Append("fileid", 4).Value = longConverter. ToBytes(219);

quslsplParms. Append("keys", cwbrcParameterTypeEnum.cwbrcInput, keys. Length).Value=keys. Bytes;
quslsplParms. Append("numberoffields", cwbrcParameterTypeEnum.cwbrcInput, 4).Value = longConverter. ToBytes(keys. Fields. Count); //number of keys to return

quslspl. Call(quslsplParms);
sc2.Bytes = quslsplParms["error"].Value;
if (((string)stringConverter. FromBytes(sc2.Fields["messageid"].Value)).Trim().Length > 0)
{
    //deal with error
    return;
}

//Get the list information from the user space
cwbx. Structure listInfo = new cwbx. Structure();
listInfo. Fields. Append("OffsetToData", 4);
listInfo. Fields. Append("DataSectionSize", 4);
listInfo. Fields. Append("NumberOfEntries", 4);
listInfo. Fields. Append("EntrySize", 4);

//The List information data structure starts at zero-based position 0x7c.   The retrieve user space
//API uses 1-based indexing.   Retreive the list information from the user space. 
cwbx. Program qusrtvus = new cwbx. Program();
qusrtvus.system = as400;
qusrtvus. LibraryName = "QSYS";
qusrtvus. ProgramName = "QUSRTVUS";
cwbx. ProgramParameters qusrtvusParms = new cwbx. ProgramParameters();
qusrtvusParms. Append("UserSpaceName", cwbrcParameterTypeEnum.cwbrcInput, 20).Value = stringConverter. ToBytes(userSpaceName);
qusrtvusParms. Append("StartingPosition", cwbrcParameterTypeEnum.cwbrcInput, 4).Value = longConverter. ToBytes(0x7c + 1);
qusrtvusParms. Append("Length", cwbrcParameterTypeEnum.cwbrcInput, 4).Value = longConverter. ToBytes(listInfo. Length);
qusrtvusParms. Append("Receiver", cwbrcParameterTypeEnum.cwbrcInout, listInfo. Length);
qusrtvusParms. Append("APIError", cwbrcParameterTypeEnum.cwbrcInout, sc2.Length).Value = sc2.Bytes;
qusrtvus. Call(qusrtvusParms);
sc2.Bytes = qusrtvusParms["APIError"].Value;
if (((string)stringConverter. FromBytes(sc2.Fields["messageid"].Value)).Trim().Length > 0)
{
    //deal with error
    return;
}
listInfo. Bytes = qusrtvusParms["Receiver"].Value;
int offsetToData = longConverter. FromBytes(listInfo. Fields["OffsetToData"].Value);
int numberOfEntries = longConverter. FromBytes(listInfo. Fields["NumberOfEntries"].Value);
int entrySize = longConverter. FromBytes(listInfo. Fields["EntrySize"].Value);

//Define the structure to receive the SPLF0200 Field data.   This is described in the QUSLSPL API. 
//Note: According to the API documentation, this is the only part that repeats for each key.   The first
//four bytes of the SPLF0200 structure is the count of keys returned. 
cwbx. Structure SPLF0200Field = new cwbx. Structure(); //individual field value data
SPLF0200Field. Fields. Append("LengthOfInformation", 4);
SPLF0200Field. Fields. Append("KeyField", 4);
SPLF0200Field. Fields. Append("TypeOfData", 1);
SPLF0200Field. Fields. Append("Reserved", 3);
SPLF0200Field. Fields. Append("LengthOfData", 4);

//Loop through each entry in the list and get the field values by key
for (int currentEntry = 0; currentEntry < numberOfEntries; currentEntry++)
{
    qusrtvusParms["StartingPosition"].Value = longConverter. ToBytes(offsetToData + (currentEntry * entrySize) + 1);
    qusrtvusParms["Length"].Value = longConverter. ToBytes(entrySize);
    qusrtvusParms["Receiver"].Length = entrySize;
    qusrtvus. Call(qusrtvusParms);
    sc2.Bytes = qusrtvusParms["APIError"].Value;
    if (((string)stringConverter. FromBytes(sc2.Fields["messageid"].Value)).Trim().Length > 0)
    {
        //deal with error
        return;
    }

    //According to the SPLF0200 format, the first 4-byte integer is the number of fields returned. 
    //After that, it's a variable list of key structures. 
    byte[] entry = qusrtvusParms["Receiver"].Value;
    byte[] numberOfFieldsReturnedBytes = new byte[4];
    Array. Copy(entry, 0, numberOfFieldsReturnedBytes, 0, 4);
    int numberOfFieldsReturned = longConverter. FromBytes(numberOfFieldsReturnedBytes);
    int lastBufferEnd = 4;

    //Fields to hold the spooled file field elements.   Note: In a production environment, I would normally
    //create a class to hold all of this, but this is just for sample purposes. 
    String spooledFileName = "";
    String userName = "";
    String opqueue = "";
    String userdata = "";
    String status = "";
    int totpages = 0;
    int copies = 0;
    String openeddate = "";
    String opentime = "";
    byte[] jobid = new byte[16];
    byte[] fileid = new byte[16];

    for (int currentField = 0; currentField < numberOfFieldsReturned; currentField++)
    {
        byte[] SPLF0200FieldBytes = new byte[SPLF0200Field. Length];
        Array. Copy(entry, lastBufferEnd, SPLF0200FieldBytes, 0, SPLF0200FieldBytes. Length);
        SPLF0200Field. Bytes = SPLF0200FieldBytes;
        int fieldDataLength = longConverter. FromBytes(SPLF0200Field. Fields["LengthOfData"].Value);
        int fieldInfoLength = longConverter. FromBytes(SPLF0200Field. Fields["LengthOfInformation"].Value);
        int fieldKey = longConverter. FromBytes(SPLF0200Field. Fields["KeyField"].Value);
        byte[] fieldDataBytes = new byte[fieldDataLength];
        Array. Copy(entry, lastBufferEnd + 16, fieldDataBytes, 0, fieldDataLength);
        lastBufferEnd = lastBufferEnd + fieldInfoLength;
        switch (fieldKey) {
            case 201:
                spooledFileName = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 203:
                userName = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 206:
                opqueue = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 209:
                userdata = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 210:
                status = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 211:
                totpages = longConverter. FromBytes(fieldDataBytes);
                break;
            case 213:
                copies = longConverter. FromBytes(fieldDataBytes);
                break;
            case 216:
                openeddate = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 217:
                opentime = stringConverter. FromBytes(fieldDataBytes);
                break;
            case 218:
                jobid = fieldDataBytes;
                break;
            case 219:
                fileid = fieldDataBytes;
                break;
        }
    }

    //All field elements that the API returned (that we care about) are loaded. 
    //Now do something with the spooled file fields here. 
}

//Delete the user space
cwbx. Program qusdltus = new cwbx. Program();
qusdltus.system = as400;
qusdltus. LibraryName = "QSYS";
qusdltus. ProgramName = "QUSDLTUS";
cwbx. ProgramParameters qusdltusParms = new cwbx. ProgramParameters();
qusdltusParms. Append("UserSpaceName", cwbrcParameterTypeEnum.cwbrcInput, 20).Value = stringConverter. ToBytes(userSpaceName);
qusdltusParms. Append("APIError", cwbrcParameterTypeEnum.cwbrcInout, sc2.Length).Value = sc2.Bytes;
qusdltus. Call(qusdltusParms);
sc2.Bytes = qusdltusParms["APIError"].Value;
if (((string)stringConverter. FromBytes(sc2.Fields["messageid"].Value)).Trim().Length > 0)
{
    //deal with error
    return;
}

