Proč nejde funkce system() (s mysql c api ) ? – C / C++ – Fórum – Programujte.com

toto je m?j zdroj?k

#include <mysql/mysql.h>

#include <stdio.h>



char prikaz[20]="ping -c 2 10.0.0.3";//totto mi  ne?lo nadefinovat lok?ln? hl?silo: 

                                     //neopr?vn?n? p??stup k pam?ti

int main()

{



MYSQL *mysql;

MYSQL_RES *res;

MYSQL_ROW row;

char* query;

char* ping;

int t,r;

mysql_init(mysql);

if (!mysql_real_connect(mysql,"localhost","root",

"ginger","ping",0,NULL,0))

printf( "Error connecting to database: %sn",mysql_error(mysql));



else printf("Connected...n");



query="select * from ip";

t=mysql_real_query(mysql,query,(unsigned int) strlen(query));

if (t)

{

printf("Error making query: %sn",

mysql_error(mysql));

}

else printf("Query made...n");

res=mysql_store_result(mysql);

row=mysql_fetch_row(res);

ping=(char *) malloc(20);

sprintf(ping,"ping -c 2 %s",row[1]);

printf("Tady by mel za??t vykon?vat ping pomoc? funkce systemn");

system("ping -c 2 10.0.0.3");

system(ping);

system(prikaz);

printf("Tady by mel skon?itn");

/*printf("po?et sloupcu=%dn",mysql_num_fields(res));

printf("po?et radku=%dn",mysql_num_rows(res));

printf("Verze serveru %sn",mysql_get_server_info(mysql));*/

mysql_free_result(res);

mysql_close(mysql);



return 0;

} 

 tommassino@tuxhouse:~/program$ ./mysql

Connected...

Query made...

Tady by mel za??t vykon?vat ping pomoc? funkce system

Tady by mel skon?it

tommassino@tuxhouse:~/program$ 

#include<stdio.h>

int main()

{

char *string;

char *ip;

char prikaz[20]="ping -c 2 10.0.0.3";

ip="10.0.0.3";

string=(char *) malloc(20);

sprintf(string,"ping -c 2 %s",ip);

printf("nnping ?islo jedna:n");

system(string);

printf("nping ?islo dva:nn");

system(prikaz);

printf("nping ?islo tri:nn");

system("ping -c 2 10.0.0.3");

return 0;

}

ping ?islo jedna:



PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.

64 bytes from 10.0.0.3: icmp_seq=1 ttl=64 time=0.187 ms

64 bytes from 10.0.0.3: icmp_seq=2 ttl=64 time=0.175 ms



--- 10.0.0.3 ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 999ms

rtt min/avg/max/mdev = 0.175/0.181/0.187/0.006 ms



ping ?islo dva:



PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.

64 bytes from 10.0.0.3: icmp_seq=1 ttl=64 time=0.182 ms

64 bytes from 10.0.0.3: icmp_seq=2 ttl=64 time=0.176 ms



--- 10.0.0.3 ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 999ms

rtt min/avg/max/mdev = 0.176/0.179/0.182/0.003 ms 



ping ?islo tri:



PING 10.0.0.3 (10.0.0.3) 56(84) bytes of data.

64 bytes from 10.0.0.3: icmp_seq=1 ttl=64 time=0.182 ms

64 bytes from 10.0.0.3: icmp_seq=2 ttl=64 time=0.173 ms



--- 10.0.0.3 ping statistics ---

2 packets transmitted, 2 received, 0% packet loss, time 999ms

rtt min/avg/max/mdev = 0.173/0.177/0.182/0.014 ms

tommassino@tuxhouse:~/program$ 

Tak me napada, jestli pri pouziti mysql, ve vasi aplikaci muzete pouzivat i jine fce vyuzivajici spojeni. Jestli by to nebylo treba dat do vlastni threadu, nebo tak neco?
Kazdopadne se o tom mozna muzete presvedcit, tak ze:
1) navazete spojeni s mysql serverem
2) vyberete pozadanovany udaj a ten ulozite do promenne
3) zavrete spojeni s MySQL serverem
4) zavolate system s pozadadovanym prikazem

POtom sem napiste, jak jste dopadl a pripadne link odkud jste stahoval MySQl soubory pro C(zajima me to).

co se t??e t?chto soubor? mysql knihoven a funkc? (a hlavi?kov?ch soubor?) tak ty se u linuxu(nev?m jak u win) v p??pad? kompilace ze zdroj?k? zkop?ruj? do adres??e s knihovnami sami.v p??pad? mysql z bin?rky(v m?m p??pad? debian) bylo pot?eba klasik? mysql-server(s nim se nainstaloval - mysql-client)a d?le je?t? bal??ek libmysqlclient-dev
Jinak toto va?e(je mi 17.5 tak?e to vyk?n? nen? t?eba :-) ) ?e??n? m? u? taky napadlo ale ??dn? zaznamenan? zm?na

tommassino napsal:

co se t??e t?chto soubor? mysql knihoven a funkc? (a hlavi?kov?ch soubor?) tak ty se u linuxu(nev?m jak u win) v p??pad? kompilace ze zdroj?k? zkop?ruj? do adres??e s knihovnami sami.v p??pad? mysql z bin?rky(v m?m p??pad? debian) bylo pot?eba klasik? mysql-server(s nim se nainstaloval - mysql-client)a d?le je?t? bal??ek libmysqlclient-dev
Jinak toto va?e(je mi 17.5 tak?e to vyk?n? nen? t?eba :-) ) ?e??n? m? u? taky napadlo ale ??dn? zaznamenan? zm?na

char prikaz[20]="ping -c 2 10.0.0.3";

char *prikaz="ping -c 2 10.0.0.3";

//pripadne, coz je jinak zapsane to same, jako vyse

char prikaz[]="ping -c 2 10.0.0.3";