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4618fdd674
In commit ecfd55795, I removed sqlda.c's checks for ndigits != 0 on the grounds that we should duplicate the state of the numeric value's digit buffer even when all the digits are zeroes. However, that still isn't quite right, because another possible state of the digit buffer is buf == digits == NULL (this occurs for a NaN). As the code now stands, it'll invoke memcpy with a NULL source address and zero bytecount, which we know a few platforms crash on. Hence, reinstate the no-copy short-circuit, but make it test specifically for buf != NULL rather than some other condition. In hindsight, the ndigits test (added by commit f2ae9f9c3) was almost certainly meant to fix the NaN case not the all-zeroes case as the associated thread alleged. As before, back-patch to all supported versions. Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905C71161@g01jpexmbkw24
src/interfaces/ecpg/README.dynSQL
descriptor statements have the following shortcomings
- input descriptors (USING DESCRIPTOR <name>) are not supported
Reason: to fully support dynamic SQL the frontend/backend communication
should change to recognize input parameters.
Since this is not likely to happen in the near future and you
can cover the same functionality with the existing infrastructure
(using s[n]printf), I'll leave the work to someone else.