if( mysql_init(&mysql) == NULL ) { syslog(LOG_USER|LOG_INFO,"inital mysql handle errorn"); return 1; } if (mysql_real_connect(&mysql,host,user,passwd,dbname,0,NULL,0) == NULL) { syslog(LOG_USER|LOG_INFO, "Failed to connect to database: Error: %sn",mysql_error(&mysql)); return 1; } else syslog(LOG_USER|LOG_INFO, "connect to database: n"); find_ps(); db_close(); return 0; } int db_close() { mysql_close(&mysql); return 0; }
int find_ps () { MYSQL_ROW m_row; MYSQL_RES *m_res; char sql[1024],username[32]; int res=1; int *id; sprintf(sql,"select id from username"); if(mysql_query(&mysql,sql) != 0) { syslog(LOG_USER|LOG_INFO, "select ps_info Error: %sn",mysql_error(&mysql)); return res; } m_res = mysql_store_result(&mysql); if(m_res==NULL) { syslog(LOG_USER|LOG_INFO, "select username Error: %sn",mysql_error(&mysql)); res = 3; return res; } if(m_row = mysql_fetch_row(m_res)) { printf("m_row=%dn",atoi(m_row[0])); res = 0; } mysql_free_result(m_res); return res; }
编译命令 gcc -g connect_db.c -L/usr/lib/mysql -lmysqlclient -lz 注意: 如果/tmp/ccTGmMS21.o: In function `main': /tmp/ccTGmMS21.o(.text+0x11): undefined reference to `mysql_init' 那么参数增加-L/usr/lib/mysql -lmysqlclient 如果 usr/lib/mysql/libmysqlclient.a(my_compress.o): In function `my_uncompress': my_compress.o(.text+0xaa): undefined reference to `uncompress' 那么增加-lz参数