PX Transform Routine compile issues - c++

Question

I have a transformer routine written in C++ that is set to clear all whitespace and map to a value if the input string is either null or empty. The c++ code compiles and has tested properly, but I am having trouble getting the routine to work in Datastage.
As per instructions, I have copied the exact compiler options that I have in my DS Environment as below.
g++ -c -O -fPIC -Wno-deprecated -m64 -mtune=generic -mcmodel=small BlankToValue.cpp
g++ -shared -m64 BlankToValue.so BlankToValue.o
When testing the routine in a job however I get the following error.
Sequential_File_36,0: Internal Error: (shbuf): iomgr/iomgr.C: 2649
Is there a different set of options I should be using for compilation?
For reference, the c++ code.
#include <stdlib.h>
#include <stdio.h>
#include <algorithm>
#include <locale.h>
#include <locale>
char * BlankToValue(char *InStr, char *RepStr)
{
if (InStr[0] == '\0') // Check for null pointer at first character of input string.
{
return RepStr; // Return replacement string if true. This is to prevent unnecessary processing.
} else
{
const char* checkstr = InStr; // Establish copy of inputstring stored in checkstring.
do { // Start outer loop.
while (isspace(*checkstr)) { // Inner loop while current checkstring byte is whitespace.
++checkstr; // Increment to next checkstring byte.
}
} while ((*InStr++ = *checkstr++)); // Set inputstring byte to current checkstring and iterate both. Breaks when either string evaluates to null.
*InStr = '\0'; // Set null terminator for input string at current byte location.
if (InStr[0] == '\0') // Checks first character of cleaned input string for null pointer.
{
return RepStr; // Return replacement string if true.
} else
{
return InStr; // Return new input string if false.
}
}
}

Answer 1

William,
in your DataStage routine definition that points to this custom function, did you select routine type as object (.o file that is compiled into transformer stage at job run time) or a library (a lib.so file that is loaded at job run time but has requirements on library naming convention and that library is located in library path). Your code above suggested you are creating a *.so file but not prefixed with lib. Here is an example:
https://www.ibm.com/support/pages/node/403041
Additionally, if the first error in job log was not a library load error but rather was the internal error (shbuf) error, I found a couple of cases where that has occurred in the past with custom routines:
Custom routine involved null handling, as does yours, and began to fail after upgrading to Information Server 8.5 when null handling rules changed in our product. The changes are explained here:
https://www.ibm.com/support/pages/node/433863
You could test if this is the issue by running the job with new job level environment variable: APT_TRANSFORM_COMPILE_OLD_NULL_HANDLING=1
In another case, the shbuf error in custom routine was the result of transformer stage receiving a large record (larger than could be handled by the datatype defined in the custom routine). Does the job still fail when using only a single sample input record with small values in all string type fields.
Thanks.

Answer 2

Also, I noticed that the error is coming from sequential file stage, rather than the transformer stage that is using the custom routine. Thus may also need to consider what is the output datatype for your custom routine and ensure that it is exiting with valid value that is not too large for the datatype and also not larger that default transport buffer size used between stages (defaults to 128k).

Answer 3

After a day or two of multiple attempts to try different compile and code approaches I found the solution to my problem. The below code was throwing a segmentation fault when passed a null column. Which makes sense in retrospect.
if (InStr[0] == '\0')
It has been corrected to the below and now everything works properly.
if ((InStr == NULL) || (InStr[0] == '\0'))