I have Raspberry pi 4B with latest raspbian and updated software. I installed hiredis
library from github source using their installation instructions. When I try to run following code on normal computer, everything works fine but on Raspberry Pi 4B redisCommand
always returns null. When I use SET
command, database is updated.
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <hiredis/hiredis.h>
int main (int argc, char **argv) {
redisReply *reply;
redisContext *c;
c = redisConnect("127.0.0.1", 6379);
if (c->err) {
printf("error: %s\n", c->errstr);
return 1;
}
/* Set a key */
reply = redisCommand(c,"SET %s %s", "test", "Hello World");
printf("SET: %s\n", reply->str);
printf("error: %s\n", c->errstr);
freeReplyObject(reply);
redisFree(c);
return 0;
}
Compilation: gcc redis-test-rw.c -o redis-test-rw -g -lhiredis
Run:
pi@rpi:~ $ ./redis-test-rw
SET: (null)
error:
pi@rpi:~ $
Redis after this call:
pi@rpi:~ $ redis-cli
127.0.0.1:6379> GET test
"Hello World"
127.0.0.1:6379>
pi@rpi:~ $
Redis MONITOR
command:
127.0.0.1:6379> MONITOR
OK
1577573389.883836 [0 127.0.0.1:47228] "SET" "test" "Hello World"
I am really confused about this because on previous Raspberry pi 3B I had no problems with hiredis and on computer it's also all right.
Thanks for advance!
Edit: Valgrind report:
$ valgrind ./redis-test-rw
==21969== Memcheck, a memory error detector
==21969== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==21969== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==21969== Command: ./redis-test-rw
==21969==
==21969== Invalid read of size 8
==21969== at 0x4865004: ??? (in /usr/lib/arm-linux-gnueabihf/libarmmem-v7l.so)
==21969== Address 0x49f964c is 36 bytes inside a block of size 42 alloc'd
==21969== at 0x4847690: malloc (vg_replace_malloc.c:309)
==21969== by 0x48907BB: redisvFormatCommand (in /usr/lib/arm-linux-gnueabihf/libhiredis.so.0.14)
==21969==
SET: (null)
error:
==21969==
==21969== HEAP SUMMARY:
==21969== in use at exit: 0 bytes in 0 blocks
==21969== total heap usage: 23 allocs, 23 frees, 1,913 bytes allocated
==21969==
==21969== All heap blocks were freed -- no leaks are possible
==21969==
==21969== For lists of detected and suppressed errors, rerun with: -s
==21969== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
Compile this sample code and verify the results:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <hiredis/hiredis.h>
int main (int argc, char **argv) {
redisReply *reply;
redisContext *c;
c = redisConnect("127.0.0.1", 6379);
if (c->err) {
printf("error: %s\n", c->errstr);
return 1;
}
/* PINGs */
reply = redisCommand(c,"PING %s", "Hello World");
printf("RESPONSE: %s\n", reply->str);
printf("error: %s\n", c->errstr);
freeReplyObject(reply);
redisFree(c);
return 0;
}
Should print:
RESPONSE: Hello World
error: