在Linux或FreeBSD系统上，无需更改就能使用下面这两个示例程序。对于其他操作系统，需要进行小的修改，主要是文件路径。设计这两个示例的目的在于，为你提供足够的细节信息，以便理解问题，它们是实际应用程序的必要组成部份。第1个示例十分直观。第2个示例采用了一些错误检查功能，略为复杂。在第1个示例的后面，给出了用于编译程序的命令行条目。在第2个示例的后面，给出了GNUmake文件，该文件可用于编译。
示例：1
test1_libmysqld.c
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include "mysql.h"
MYSQL *mysql;
MYSQL_RES *results;
MYSQL_ROW record;
static char *server_options[] = { "mysql_test", "--defaults-file=my.cnf" };
int num_elements = sizeof(server_options)/ sizeof(char *);
static char *server_groups[] = { "libmysqld_server", "libmysqld_client" };
int main(void)
{
mysql_server_init(num_elements, server_options, server_groups);
mysql = mysql_init(NULL);
mysql_options(mysql, MYSQL_READ_DEFAULT_GROUP, "libmysqld_client");
mysql_options(mysql, MYSQL_OPT_USE_EMBEDDED_CONNECTION, NULL);
mysql_real_connect(mysql, NULL,NULL,NULL, "database1", 0,NULL,0);
mysql_query(mysql, "SELECT column1, column2 FROM table1");
results = mysql_store_result(mysql);
while((record = mysql_fetch_row(results))) {
printf("%s - %s \n", record[0], record[1]);
}
mysql_free_result(results);
mysql_close(mysql);
mysql_server_end();
return 0;
}
下面给出了编译上述程序的命令行命令：
gcc test1_libmysqld.c -o test1_libmysqld -lz \
`/usr/local/mysql/bin/mysql_config --include --libmysqld-libs`
示例：2
要想检验该示例，创建一个与MySQL源目录同级的test2_libmysqld目录。将test2_libmysqld.c源文件和GNUmakefile保存到该目录，并在test2_libmysqld目录下运行GNU make。
test2_libmysqld.c
/*
* A simple example client, using the embedded MySQL server library
*/
#include <mysql.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
MYSQL *db_connect(const char *dbname);
void db_disconnect(MYSQL *db);
void db_do_query(MYSQL *db, const char *query);
const char *server_groups[] = {
"test2_libmysqld_SERVER", "embedded", "server", NULL
};
int
main(int argc, char **argv)
{
MYSQL *one, *two;
/* mysql_server_init() must be called before any other mysql
* functions.
*
* You can use mysql_server_init(0, NULL, NULL), and it
* initializes the server using groups = {
* "server", "embedded", NULL
* }.
*
* In your $HOME/.my.cnf file, you probably want to put:
[test2_libmysqld_SERVER]
language = /path/to/source/of/mysql/sql/share/english
* You could, of course, modify argc and argv before passing
* them to this function. Or you could create new ones in any
* way you like. But all of the arguments in argv (except for
* argv[0], which is the program name) should be valid options
* for the MySQL server.
*
* If you link this client against the normal mysqlclient
* library, this function is just a stub that does nothing.
*/
mysql_server_init(argc, argv, (char **)server_groups);
one = db_connect("test");
two = db_connect(NULL);
db_do_query(one, "SHOW TABLE STATUS");
db_do_query(two, "SHOW DATABASES");
mysql_close(two);
mysql_close(one);
/* This must be called after all other mysql functions */
mysql_server_end();
exit(EXIT_SUCCESS);
}
static void
die(MYSQL *db, char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
(void)putc('\n', stderr);
if (db)
db_disconnect(db);
exit(EXIT_FAILURE);
}
MYSQL *
db_connect(const char *dbname)
{
MYSQL *db = mysql_init(NULL);
if (!db)
die(db, "mysql_init failed: no memory");
/*
* Notice that the client and server use separate group names.
* This is critical, because the server does not accept the
* client's options, and vice versa.
*/
mysql_options(db, MYSQL_READ_DEFAULT_GROUP, "test2_libmysqld_CLIENT");
if (!mysql_real_connect(db, NULL, NULL, NULL, dbname, 0, NULL, 0))
die(db, "mysql_real_connect failed: %s", mysql_error(db));
return db;
}
void
db_disconnect(MYSQL *db)
{
mysql_close(db);
}
void
db_do_query(MYSQL *db, const char *query)
{
if (mysql_query(db, query) != 0)
goto err;
if (mysql_field_count(db) > 0)
{
MYSQL_RES *res;
MYSQL_ROW row, end_row;
int num_fields;
if (!(res = mysql_store_result(db)))
goto err;
num_fields = mysql_num_fields(res);
while ((row = mysql_fetch_row(res)))
{
(void)fputs(">> ", stdout);
for (end_row = row + num_fields; row < end_row; ++row)
(void)printf("%s\t", row ? (char*)*row : "NULL");
(void)fputc('\n', stdout);
}
(void)fputc('\n', stdout);
mysql_free_result(res);
}
else
(void)printf("Affected rows: %lld\n", mysql_affected_rows(db));
return;
err:
die(db, "db_do_query failed: %s [%s]", mysql_error(db), query);
}
GNUmakefile
# This assumes the MySQL software is installed in /usr/local/mysql
inc := /usr/local/mysql/include/mysql
lib := /usr/local/mysql/lib
# If you have not installed the MySQL software yet, try this instead
#inc := $(HOME)/mysql-5.1/include
#lib := $(HOME)/mysql-5.1/libmysqld
CC := gcc
CPPFLAGS := -I$(inc) -D_THREAD_SAFE -D_REENTRANT
CFLAGS := -g -W -Wall
LDFLAGS := -static
# You can change -lmysqld to -lmysqlclient to use the
# client/server library
LDLIBS = -L$(lib) -lmysqld -lz -lm -lcrypt
ifneq (,$(shell grep FreeBSD /COPYRIGHT 2>/dev/null))
# FreeBSD
LDFLAGS += -pthread
else
# Assume Linux
LDLIBS += -lpthread
endif
# This works for simple one-file test programs
sources := $(wildcard *.c)
objects := $(patsubst %c,%o,$(sources))
targets := $(basename $(sources))
all: $(targets)
clean:
rm -f $(targets) $(objects) *.core
