嵌入式linux開發中，有時候為了定位問題，需要查看某個進程的各個線程的運行情況。

例子

multi_thread.c：

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#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

// 線程名稱最大長度
#define App_THREAD_NAME_MAX_LEN     32

// 線程索引
typedef enum _app_thread_index
{
    APP_THREAD_INDEX_TEST0,
    APP_THREAD_INDEX_TEST1,
    APP_THREAD_INDEX_TEST2,
    APP_THREAD_INDEX_TEST3,
    APP_THREAD_INDEX_TEST4,
    APP_THREAD_INDEX_TEST5,
    APP_THREAD_INDEX_MAX
}app_thread_index_e;

// 線程入口函數指針類型
typedef void *(*p_thread_fun)(void *param);

// 線程數據表
typedef struct _app_thread
{
    pthread_t thread_handle;
    p_thread_fun thread_entry;
    char name[APP_THREAD_NAME_MAX_LEN];
}app_thread_s;

static void *test0_thread_entry(void *param);
static void *test1_thread_entry(void *param);
static void *test2_thread_entry(void *param);
static void *test3_thread_entry(void *param);
static void *test4_thread_entry(void *param);
static void *test5_thread_entry(void *param);

// 線程表
app_thread_s s_app_thread_table[APP_THREAD_INDEX_MAX] =
{
    {0, test0_thread_entry, "test0_thread"},
    {0, test1_thread_entry, "test1_thread"},
    {0, test2_thread_entry, "test2_thread"},
    {0, test3_thread_entry, "test3_thread"},
    {0, test4_thread_entry, "test4_thread"},
    {0, test5_thread_entry, "test5_thread"}
};

static void *test0_thread_entry(void *param)
{
    printf("test0_thread running...n");

    while (1)
    {
        usleep(2 * 1000);
    }
    
    return NULL;
}

static void *test1_thread_entry(void *param)
{
    printf("test1_thread running...n");

    while (1)
    {
        usleep(2 * 1000);
    }
    
    return NULL;
}

static void *test2_thread_entry(void *param)
{
    printf("test2_thread running...n");

    while (1)
    {
        usleep(2 * 1000);
    }
    
    return NULL;
}

static void *test3_thread_entry(void *param)
{
    printf("test3_thread running...n");

    while (1)
    {
        usleep(2 * 1000);
    }
    
    return NULL;
}

static void *test4_thread_entry(void *param)
{
    printf("test4_thread running...n");

    while (1)
    {
        usleep(2 * 1000);
    }
    
    return NULL;
}

static void *test5_thread_entry(void *param)
{
    printf("test5_thread running...n");

    while (1)
    {
        usleep(2 * 1000);
    }
    
    return NULL;
};

static int create_all_app_thread(void)
{
    int ret = 0;

    for (int i = 0; i < APP_THREAD_INDEX_MAX; i++)
    {
        ret = pthread_create(&s_app_thread_table[i].thread_handle, NULL, s_app_thread_table[i].thread_entry, NULL);

        if (0 != ret)
        {
            printf("%s thread create error! thread_id = %ldn", s_app_thread_table[i].name, s_app_thread_table[i].thread_handle);
            return ret;
        }
        else
        {
            printf("%s thread create success! thread_id = %ldn", s_app_thread_table[i].name, s_app_thread_table[i].thread_handle);
            pthread_setname_np(s_app_thread_table[i].thread_handle, s_app_thread_table[i].name);
        }

        pthread_detach(s_app_thread_table[i].thread_handle);
    }

    return ret;
}

int main(int argc, char **argv)
{ 
    create_all_app_thread();
    
    while (1)
    {
        usleep(2 * 1000);
    }

    return 0;
}

我們可以通過top命令來查看。要在top輸出中開啟線程查看，請調用top命令的“-H”選項，該選項會列出所有Linux線程。

這里我們指定查看multi_thread進程的各線程運行情況，命令：