Text fields longer than 1040 chars cause php to core dump during select.
Reproduce with:

for ($i = 0; $i <2200; ++$i) {
    $text .= "x";
}
 
echo "Drop=", sybase_query("drop table t"), "\n";
echo "Create=", sybase_query("create table t (t text)"), "\n";
echo "Insert=", sybase_query("insert into t values ('$text')"), "\n";
echo "Select=", sybase_query("select t from t"), "\n";

If I run this I see:
Drop=1
Create=1
Insert=1
Segmentation fault

If I reduce 2200 down to 1000 I see:
Drop=1
Create=1
Insert=1
Select=2

php3.ini:
sybase.interface_file=/tools1/pkgs/sybase/interfaces
doc_root=/web/cgi-bin/RC_internal/phpdir/scripts

Do-conf:
./configure --with-gd=no --with-sybase=/tools1/pkgs/sybase --with-config-file-path=/web/cgi-bin/RC_internal/phpdir/lib --enable-debug=no --enable-safe-mode=yes --with-exec-dir=/web/cgi-bin/RC_internal/phpdir/scripts --bindir=/web/cgi-bin/RC_internal/phpdir/bin