gcc app.c -o app $(/usr/local/apr/bin/apr-1-config --cflags --cppflags --includes --link-ld --libs)

gcc app.c -o app $(/usr/local/apr/bin/apr-1-config --cflags --cppflags --includes --link-ld) $(/usr/local/apr/bin/apu-1-config --link-ld --libs)

rv = apr_pool_create(&pool, NULL);
char *msg = apr_pstrcat(pool, "Hello, ", "APR ", "pool!", NULL);
void *buf = apr_palloc(pool, 128);
apr_pool_destroy(pool);

Hello, APR pool!
psprintf demo: 2 + 3 = 5
pstrdup equals msg: yes
apr_palloc(128) OK, pool addr=0x5641976153b8

char *msg   = apr_pstrcat(pool, "Hello, ", "APR ", "pool!", NULL);
char *line  = apr_psprintf(pool, "psprintf demo: %d + %d = %d", 2, 3, 5);
char *copy  = apr_pstrdup(pool, msg);

Hello, APR pool!
psprintf demo: 2 + 3 = 5
pstrdup equals msg: yes

/* 以创建|写入|截断方式打开并写入 */
rv = apr_file_open(&fp, path, APR_CREATE | APR_WRITE | APR_TRUNCATE,
                   APR_OS_DEFAULT, pool);
const char *text = "Apache APR file I/O demo.\n第二行：UTF-8 中文内容。\n";
apr_size_t len = strlen(text);
rv = apr_file_write(fp, text, &len);   /* len 返回实际写入 60 */

/* 取文件大小并读回 */
apr_finfo_t finfo;
apr_file_info_get(&finfo, APR_FINFO_SIZE, fp);
apr_size_t nread = sizeof(buf) - 1;
rv = apr_file_read(fp, buf, &nread);   /* nread 返回实际读取字节数 */

apr_file_write wrote 60 bytes
file size: 60 bytes
read 60 bytes:
Apache APR file I/O demo.
第二行：UTF-8 中文内容。
old path gone after rename (rv=2)

apr_uuid_t uuid, parsed;
char buf[APR_UUID_FORMATTED_LENGTH + 1];   /* 36 字符 + 结尾 0 */
apr_uuid_get(&uuid);
apr_uuid_format(buf, &uuid);
rv = apr_uuid_parse(&parsed, buf);         /* 解析回结构，可再 format 验证一致 */

# ./demo_uuid
uuid#1: e4b33c28-c5d6-11f1-b461-8781a5106fe2
uuid#2: e4b33d90-c5d6-11f1-b461-8781a5106fe2
parse+format roundtrip: match (rv=0, len=36)
# ./demo_uuid
uuid#1: e4b3c67a-c5d6-11f1-a321-193684b9e0dc
uuid#2: e4b3c80a-c5d6-11f1-a321-193684b9e0dc
parse+format roundtrip: match (rv=0, len=36)

rv = apr_initialize();
if (rv != APR_SUCCESS) {
    char errbuf[256];
    apr_strerror(rv, errbuf, sizeof(errbuf));
    fprintf(stderr, "apr_initialize failed: %s\n", errbuf);
    return 1;
}

/* demo_mutex.c：apr_thread_create 多线程 + apr_thread_mutex 互斥锁示例 */
#include <stdio.h>
#include <stdlib.h>
#include <apr_general.h>
#include <apr_pools.h>
#include <apr_thread_proc.h>
#include <apr_thread_mutex.h>

#define WORKER_COUNT 4
#define INC_PER_WORKER 10000

static apr_thread_mutex_t *lock;
static long long counter = 0;

static void *APR_THREAD_FUNC worker(apr_thread_t *thd, void *data)
{
    int i;
    for (i = 0; i < INC_PER_WORKER; i++) {
        apr_thread_mutex_lock(lock);
        counter++;
        apr_thread_mutex_unlock(lock);
    }
    return NULL;
}

int main(int argc, const char *argv[])
{
    apr_initialize();
    atexit(apr_terminate);
    apr_pool_t *pool;
    apr_pool_create(&pool, NULL);

    /* 创建默认类型互斥锁 */
    apr_thread_mutex_create(&lock, APR_THREAD_MUTEX_DEFAULT, pool);

    /* 创建 4 个工作线程，各累加 10000 次 */
    apr_thread_t *threads[WORKER_COUNT];
    for (int i = 0; i < WORKER_COUNT; i++) {
        apr_status_t rv = apr_thread_create(&threads[i], NULL, worker, NULL, pool);
        if (rv != APR_SUCCESS) {
            fprintf(stderr, "apr_thread_create failed\n");
            return 1;
        }
    }
    /* join 等待全部线程结束 */
    for (int i = 0; i < WORKER_COUNT; i++) {
        apr_status_t rv;
        apr_thread_join(&rv, threads[i]);
    }

    printf("expect %d workers x %d inc = %d\n", WORKER_COUNT, INC_PER_WORKER,
           WORKER_COUNT * INC_PER_WORKER);
    printf("counter = %lld (%s)\n", counter,
           counter == (long long)WORKER_COUNT * INC_PER_WORKER ? "mutex works" : "RACE!");
    apr_thread_mutex_destroy(lock);
    apr_pool_destroy(pool);
    return 0;
}

cd /root/apr-demo
gcc demo_mutex.c -o demo_mutex $(/usr/local/apr/bin/apr-1-config --cflags --cppflags --includes --link-ld --libs)
./demo_mutex

# ./demo_mutex
expect 4 workers x 10000 inc = 40000
counter = 40000 (mutex works)
# ./demo_mutex
expect 4 workers x 10000 inc = 40000
counter = 40000 (mutex works)
# ./demo_mutex
expect 4 workers x 10000 inc = 40000
counter = 40000 (mutex works)

/* demo_net.c：apr_socket 回环 TCP 通信示例（同一进程内 listen/connect/accept/send/recv） */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <apr_general.h>
#include <apr_pools.h>
#include <apr_network_io.h>

#define TEST_PORT 18080

int main(int argc, const char *argv[])
{
    apr_initialize();
    atexit(apr_terminate);
    apr_pool_t *pool;
    apr_pool_create(&pool, NULL);

    apr_status_t rv;
    char errbuf[256];

    /* 1) 构造 127.0.0.1:18080 地址，创建监听 socket 并 bind/listen */
    apr_sockaddr_t *sa;
    rv = apr_sockaddr_info_get(&sa, "127.0.0.1", APR_INET, TEST_PORT, 0, pool);
    if (rv != APR_SUCCESS) {
        apr_strerror(rv, errbuf, sizeof(errbuf));
        fprintf(stderr, "apr_sockaddr_info_get failed: %s\n", errbuf);
        return 1;
    }
    apr_socket_t *lsn, *conn, *cli;
    rv = apr_socket_create(&lsn, sa->family, SOCK_STREAM, APR_PROTO_TCP, pool);
    if (rv != APR_SUCCESS) {
        apr_strerror(rv, errbuf, sizeof(errbuf));
        fprintf(stderr, "apr_socket_create(listen) failed: %s\n", errbuf);
        return 1;
    }
    apr_socket_opt_set(lsn, APR_SO_REUSEADDR, 1);
    rv = apr_socket_bind(lsn, sa);
    if (rv != APR_SUCCESS) {
        apr_strerror(rv, errbuf, sizeof(errbuf));
        fprintf(stderr, "apr_socket_bind failed: %s\n", errbuf);
        return 1;
    }
    rv = apr_socket_listen(lsn, 5);
    if (rv != APR_SUCCESS) {
        apr_strerror(rv, errbuf, sizeof(errbuf));
        fprintf(stderr, "apr_socket_listen failed: %s\n", errbuf);
        return 1;
    }

    /* 2) 创建客户端 socket 并 connect 监听端口 */
    apr_socket_create(&cli, sa->family, SOCK_STREAM, APR_PROTO_TCP, pool);
    rv = apr_socket_connect(cli, sa);
    if (rv != APR_SUCCESS) {
        apr_strerror(rv, errbuf, sizeof(errbuf));
        fprintf(stderr, "apr_socket_connect failed: %s\n", errbuf);
        return 1;
    }
    printf("client connected to 127.0.0.1:%d\n", TEST_PORT);

    /* 3) 服务端 accept 取得连接；客户端发送一条数据 */
    rv = apr_socket_accept(&conn, lsn, pool);
    if (rv != APR_SUCCESS) {
        apr_strerror(rv, errbuf, sizeof(errbuf));
        fprintf(stderr, "apr_socket_accept failed: %s\n", errbuf);
        return 1;
    }
    const char *msg = "hello from apr_socket client";
    apr_size_t len = strlen(msg);
    rv = apr_socket_send(cli, msg, &len);
    printf("client sent %ld bytes\n", (long)len);

    /* 4) 服务端接收并打印 */
    char buf[128];
    apr_size_t nrecv = sizeof(buf) - 1;
    rv = apr_socket_recv(conn, buf, &nrecv);
    buf[nrecv] = 0;
    printf("server recv %ld bytes: %s\n", (long)nrecv, buf);

    /* 5) 服务端回写应答，客户端接收 */
    const char *reply = "ack from apr_socket server";
    len = strlen(reply);
    apr_socket_send(conn, reply, &len);
    nrecv = sizeof(buf) - 1;
    rv = apr_socket_recv(cli, buf, &nrecv);
    buf[nrecv] = 0;
    printf("client recv %ld bytes: %s\n", (long)nrecv, buf);

    apr_socket_close(cli);
    apr_socket_close(conn);
    apr_socket_close(lsn);
    apr_pool_destroy(pool);
    return 0;
}

cd /root/apr-demo
gcc demo_net.c -o demo_net $(/usr/local/apr/bin/apr-1-config --cflags --cppflags --includes --link-ld --libs)
./demo_net

# ./demo_net
client connected to 127.0.0.1:18080
client sent 28 bytes
server recv 28 bytes: hello from apr_socket client
client recv 26 bytes: ack from apr_socket server
# ./demo_net
client connected to 127.0.0.1:18080
client sent 28 bytes
server recv 28 bytes: hello from apr_socket client
client recv 26 bytes: ack from apr_socket server

gcc demo_uuid.c -o demo_uuid $(/usr/local/apr/bin/apr-1-config --cflags --cppflags --includes --link-ld) $(/usr/local/apr/bin/apu-1-config --link-ld --libs)

echo "/usr/local/apr/lib" > /etc/ld.so.conf.d/apr.conf && ldconfig

char *msg = apr_pstrcat(pool, "Hello, ", "APR ", "pool!", NULL);   /* 末参必须是 NULL */