I've been attempting for a while to figure out how to pass arrays of integers back and forth from a custom c-library that I'd like to plug into my server instance. Although I'm able to usefully pass single integers to a functions I've written, the best I've been able to accomplish passing in pointers and const pointers is to blow up the server. I've only attempted compiling per the instructions <a href="
http://www.postgresql.org/docs/current/static/xfunc-c.html">here</a>. I wanted to check with this list first before spending any time delving into libpq for fear that it was the wrong rabbit-hole to go looking into in the first place.
The basic idea (in pseudo-code) is to implement the following rather simple algorithm:
int*
and_function(const int* arr1, const int* arr2){
int sz = sizeof( arr1 ); // or obtain from another param...
// memcpy data over for arr1, arr2...
int[sz] r_arr = (int*) palloc( VARHDRZ + sz );
int i;
for( i=0; i<sz; i++ ){
r_arr[i] = arr1 & arr2;
}
return r_arr;
}
It seems that when I attempt to call the function with either "version 0" or "version 1" syntax, the dynamic binding confuses the server even though my
CREATE OR REPLACE FUNCTION and_function(int[]) RETURNS int[] ... is syntactically correct and the library is located appropriately.
--bash-3.00$ /opt/postgres/bin/pg_config --version
PostgreSQL 8.2.3
I apologize in advance if my problem arises from c-ignorance.
Any suggestions?
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Jason Nerothin
Programmer/Analyst IV - Database Administration
UCLA-DOE Institute for Genomics & Proteomics
Howard Hughes Medical Institute
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611 C.E. Young Drive East | Tel: (310) 206-3907
105 Boyer Hall, Box 951570 | Fax: (310) 206-3914
Los Angeles, CA 90095. USA | Mail:
jason@mbi.ucla.edu========================================================
http://www.mbi.ucla.edu/~jason========================================================
