[英]return argument (struct) from a thread
我有一個函數task1,該函數由主線程(純C)中的pthread_create調用。 它可以工作,但是線程結束后,我對my_pair所做的任何操作都會丟失。 我的意思是我希望創建的線程task1進行操作並將其保存在eventT上。是否可以返回my_pair? 怎么樣?
void task1(void* eventT){
//struct eventStruct *my_pair = (struct eventStruct*)eventT;
// Tried with malloc but same wrong behavior
struct eventStruct *my_pair = malloc(sizeof((struct eventStruct*)eventT));
// do stuff
my_pair->text = TRIAL;
pthread_exit( my_pair );
}
// Global variable
struct eventStruct *eventT = NULL;
//Calling the thread from the main
eventT = (struct eventStruct*)
thpool_add_work(thpool, (void*)task1, (void*) &eventT);
// Expecting eventT changed (not happening..)
pthread_join( thread, &eventT );
這是從線程返回結構的一種方法的示例-通過傳入分配的結構以使線程返回。 此示例與您發布的代碼類似,但是僅使用pthread
函數,因為我對thpool_add_work()
API thpool_add_work()
。
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
struct eventStruct
{
char const* text;
char const* more_text;
};
#define TRIAL "this is a test"
void* task1(void* eventT)
{
struct eventStruct *my_pair = (struct eventStruct*)eventT;
// do stuff
my_pair->text = TRIAL;
pthread_exit( my_pair );
}
int main(void)
{
pthread_t thread;
struct eventStruct* thread_arg = malloc(sizeof *thread_arg);
thread_arg->text = "text initialized";
thread_arg->more_text = "more_text_initialized";
//Calling the thread from the main
pthread_create( &thread, NULL, task1, thread_arg);
void* thread_result;
pthread_join( thread, &thread_result);
struct eventStruct* eventT = thread_result;
puts(eventT->text);
puts(eventT->more_text);
free(eventT);
return 0;
}
可以完成此操作的另一種方法是讓返回的結構由線程分配,而不是由調用者分配,然后將其傳遞。我確定可以使用許多其他機制,但這應該可以幫助您入門。
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