ColumnName and ColumnNumber in libpq (C interface)

I think this behaviour is not fine:
I create a table with
CREATE TABLE foo ("Bar" VARCHAR(1));

I thougth running this helloworldish C program:

#include <stdio.h>
#include <libpq-fe.h>
int main(int argc,char **argv)
{       PGconn * conn = PQconnectdb("dbname=pruebas");       PGresult * res = PQexec(conn,"SELECT * from foo");
printf("%s\n",PQfname(res,0));      printf("%d\n",PQfnumber(res,"Bar"));       PQfinish(conn);
 
}

should print 

Bar
0

but stdout shows

Bar
-1

What is happening? Any ideas? Is this a bug, a feature or something I'm missing?

-- 
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Alberto Cabello Sánchez
alberto@unex.es
Servicio de Informática
924 289 351
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