在嵌入式Linux開發(fā)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：

左右滑動查看全部代碼>>>

#define?_GNU_SOURCE
#include?
#include?
#include?
#include?

//?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(shù)指針類型
typedef?void?*(*p_thread_fun)(void?*param);

//?線程數(shù)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...
");

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

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

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

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

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

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

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

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

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

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

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

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

????for?(int?i?=?0;?i?NULL,?s_app_thread_table[i].thread_entry,?NULL);

????????if?(0?!=?ret)
????????{
????????????printf("%s?thread?create?error!?thread_id?=?%ld
",?s_app_thread_table[i].name,?s_app_thread_table[i].thread_handle);
????????????return?ret;
????????}
????????else
????????{
????????????printf("%s?thread?create?success!?thread_id?=?%ld
",?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，具體做法就是要在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：

top?-H?-p?`pidof?multi_thread`

注意：這里的 `號并不是單引號！！！

這個符號在鍵盤上感嘆號!鍵的左邊。

我們先運行程序，再使用top命令查看，比如：

注意：我們創(chuàng)建線程的時候需要使用 pthread_setname_np 函數(shù)設置線程的名字，否則top -H顯示不出來具體的線程。

假如我們把上例中的pthread_setname_np屏蔽掉，結果如下：

可見，不調用pthread_setname_np設置線程名稱的話，top -H查看得到的各線程名稱就是進程名。