Where to find out more about C's functions like cvtch and cvthc

[Dave Murvin <davem@xxxxxxxx>]

I have been looking through the archives for information on converting 
characters to hex.  I found several sample prototypes such as the following 
from Barbara Morris:

    D cvthex1To2       Pr                  Extproc('cvthc')
     D  longReceiver                   *   Value
     D  shortSource                    *   Value
     D  receiverBytes                10i 0 Value

     D cvthex2To1       Pr                  Extproc('cvtch')
     D  shortReceiver                  *   Value
     D  longSource                     *   Value
     D  sourceBytes                  10i 0 Value

What I have not been able to find is where these procedures are documented 
so I can figure out how to use this type of procedure (and other C function 
procedures) myself.  When I search the Info Center for the Convert 
Character to Hex procedure, what I get is the following, which does not 
look like the prototypes to me.


Convert Character to Hex (CVTCH)


Op Code (Hex) Operand 1 Operand 2

1082 Receiver Source

Operand 1: Character variable scalar.

Operand 2: Character variable scalar.

Description:   Each character (8-bit value) of the string value in the 
source operand is converted to a hex digit (4-bit value) and placed in the 
receiver operand. The source operand characters must relate to valid hex 
digits or a conversion  (hex 0C01) exception is signaled.
Characters Hex Digits
Hex F0-hex F9 Hex 0-hex 9
Hex C1-hex C6 Hex A-hex F
The operation begins with the two operands left-adjusted and proceeds left 
to right until all the hex digits of the receiver operand have been filled. 
If the source operand is too small, it is logically padded on the right 
with zero characters (hex F0). If the source operand is too large, a length 
conformance  (hex 0C08) exception or an invalid operand length  (hex 2A0A) 
exception is signaled.

Substring operand references that allow for a null substring reference (a 
length value of zero) may be specified for operands 1 and 2. The effect of 
specifying a null substring reference for the source is that the bytes of 
the receiver are each set with a value of hex 00. The effect of specifying 
a null substring reference for the receiver is that no result is set.

Is there a manual on this?  If so, can someone let me know where to find 
it?  I have looked at the ILE C/C++ run time library manual and these 
functions do not appear to be there.

Thanks for the help.


Dave Murvin
DRM Enterprises, Inc.