uint length= (uint)(row->data[i+1] - row->data[i] - 1);

      if (!row->data[i] || row->data[i][length])

        goto error;

$ mariadb --version

mariadb from 11.6.0-MariaDB, client 15.2 for Linux (x86_64) using readline 5.1

$ cc mc6a.c

$ ./a.out &

$ echo 'SELECT * FROM t;' | mariadb --host=127.0.0.1 --ssl=off d

Segmentation fault (core dumped)

Program terminated with signal SIGSEGV, Segmentation fault.

#0  0x00005624146ec687 in unpack_fields (mysql=0x562414c09000 <mysql>, data=0x562415e5ca50, alloc=0x562414c09300 <mysql+768>, fields=1, 

    default_value=1 '\001') at /home/rtm/maria/server/libmariadb/libmariadb/mariadb_lib.c:1068

1068          if (!row->data[i] || row->data[i][length])

(gdb) where

#0  0x00005624146ec687 in unpack_fields (mysql=0x562414c09000 <mysql>, data=0x562415e5ca50, alloc=0x562414c09300 <mysql+768>, fields=1, 

    default_value=1 '\001') at /home/rtm/maria/server/libmariadb/libmariadb/mariadb_lib.c:1068

#1  0x00005624146f2711 in mthd_my_read_query_result (mysql=0x562414c09000 <mysql>) at /home/rtm/maria/server/libmariadb/libmariadb/mariadb_lib.c:2892

#2  0x00005624146f2ad8 in mysql_real_query (mysql=0x562414c09000 <mysql>, query=0x562415e56138 "SELECT * FROM t", length=15)

    at /home/rtm/maria/server/libmariadb/libmariadb/mariadb_lib.c:2959

#3  0x00005624146dd3a2 in mysql_real_query_for_lazy (buf=0x562415e56138 "SELECT * FROM t", length=15) at /home/rtm/maria/server/client/mysql.cc:3209

#4  0x00005624146de2e9 in com_go (buffer=0x562414c095a0 <glob_buffer>) at /home/rtm/maria/server/client/mysql.cc:3480

#5  0x00005624146dbc1b in add_line (buffer=..., line=0x562415e55098 "SELECT * FROM t;", line_length=16, in_string=0x7ffe6265a8c6 "", 

    ml_comment=0x7ffe6265a8c7, truncated=false) at /home/rtm/maria/server/client/mysql.cc:2643

#6  0x00005624146dad87 in read_and_execute (interactive=false) at /home/rtm/maria/server/client/mysql.cc:2338

#7  0x00005624146d9534 in main (argc=12, argv=0x562415e533e0) at /home/rtm/maria/server/client/mysql.cc:1397

(gdb) print row->data[i]

$1 = 0x562415eef89c "c"

(gdb) print row->data[i+1]

$2 = 0x0

(gdb) print length

$3 = 3926984547