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Part of my standards is that every procedure has a test program that will display all values returned by the procedure.
Seems to me that it'd be more useful to display the data that the pointer points to. I have yet to meet the programmer who can take a value like SPP:D572811D4306B980 and say "hey! that's not right! That API is supposed to return SPP:D572811A4306B980!"
But, having said that, it's certainly possible to display the value of a pointer.
There are other ways to determine if the procedures worked. I just like the idea of displaying the pointer value, and was looking for an easy way. After all, it's just a number. There should be a way to convert it to a display value.
A pointer _isn't_ just a number on the iSeries. You may be thinking of a PC or Unix environment where a pointer is an integer. On the iSeries, a pointer is significantly more complex, it contains several different pieces of information that enable it to access any memory anywhere in either teraspace or single-level store. There are many types of pointers, system pointers, space pointers, procedure pointers, invocation pointers, suspend pointers, data pointers, label pointers... the format of the data in the pointer itself will be different depending on the type of pointer.
But, anyway, yeah you can display a pointer. Two ways that come to mind:a) You could use the cvthc() API to read the contents of the pointer (just by specifying where the pointer is stored in memory) and it'll output a raw hex representation of the bytes that make up the pointer.
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For example:
D cvthc PR ExtProc('cvthc')
D target 32A
D src_bits * value
D tgt_length 10I 0 value
D myPointer s *
D rawHexData s 32A
/free
cvthc(rawHexData: %addr(myPointer): %size(rawHexData));
b) The printf() family of functions in ILE C has the ability to make a
nicely formatted dump of the various pieces of info in a pointer. It's
relatively easy for an RPG program to call the snprintf() API from ILE C
to format the pointer:
D snprintf PR 10I 0 extproc('snprintf')
d buf 32767A options(*varsize)
D bufsize 10U 0 value
D fmt * value options(*string)
D ptr * value options(*nopass)
D temp s 81A
D humanData s 80A
/free
snprintf(temp: %size(temp): '%p': myPointer);
humanData = %str(%addr(temp));
Since snprintf() writes out a C-style string (i.e. null-terminated
string), I write it to a temporary field, and then I use the %str() BIF to
extract it into an RPG-style character field.
Either of these could be used for your purposes if you really want to print the contents of a pointer. Here's a sample program (in fact, it's where the code snippets above came from) that demonstrates printing a standard space pointer, a procedure pointer, and a teraspace pointer. Each pointer is printed using both methods:
H DFTACTGRP(*NO) BNDDIR('QC2LE')
FQSYSPRT O F 132 PRINTER
D TS_malloc PR * ExtProc('_C_TS_malloc')
D size 10U 0 value
D TS_free PR ExtProc('_C_TS_free')
D ptr * value
D snprintf PR 10I 0 extproc('snprintf')
d buf 32767A options(*varsize)
D bufsize 10U 0 value
D fmt * value options(*string)
D ptr * value options(*nopass)
D snprintf2 PR 10I 0 extproc('snprintf')
d buf 32767A options(*varsize)
D bufsize 10U 0 value
D fmt * value options(*string)
D ptr * value procptr options(*nopass)
D cvthc PR ExtProc('cvthc')
D target 32A
D src_bits * value
D tgt_length 10I 0 value
D myPointer s *
D procPtr s * procptr
D rawHexData s 32A
D temp s 81A
D humanData s 80A
/free
// Use cvthc() to create a hex dump of the contents
// of a pointer.
//
// Use sprintf() to format a pointer's contents to make
// it easier for a person to read.
myPointer = %alloc(1234);
cvthc(rawHexData: %addr(myPointer): %size(rawHexData));
snprintf(temp: %size(temp): '%p': myPointer);
humanData = %str(%addr(temp));
except;
dealloc myPointer;
// now try it with a procedure pointer:
procPtr = %paddr(snprintf);
cvthc(rawHexData: %addr(procPtr): %size(rawHexData));
snprintf2(temp: %size(temp): '%p': procPtr);
humanData = %str(%addr(temp));
except;
// now try it with a teraspace pointer:
myPointer = TS_malloc(54321);
cvthc(rawHexData: %addr(myPointer): %size(rawHexData));
snprintf(temp: %size(temp): '%p': myPointer);
humanData = %str(%addr(temp));
TS_free(myPointer);
except;
*inlr = *on;
/end-free
OQSYSPRT E
O 'Raw Hex='
O rawHexData +0
O E
O 'Human Readable='
O humanData +0
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