vfork

Using fork(), how can I make child process run always first?

由 我的未来我决定 提交于 2021-01-15 06:38:42
问题 Child and parent process execution is parallel and which starts first depends on OS scheduling. But what can be done to start child always before the parent? This is the pseudo code for my problem, int start_test() { pid_t pid; pid = fork(); if(pid == 0) { execv("XXX", XXX); } else if(pid > 0) { pid = fork(); if(pid == 0) { execv("XXX", XXX); } else { // Do something } } return 0; } int main() { start_test(); return 0; } I wants to make first execv execute first than parent creates new

Using fork(), how can I make child process run always first?

由 扶醉桌前 提交于 2021-01-15 06:36:26
问题 Child and parent process execution is parallel and which starts first depends on OS scheduling. But what can be done to start child always before the parent? This is the pseudo code for my problem, int start_test() { pid_t pid; pid = fork(); if(pid == 0) { execv("XXX", XXX); } else if(pid > 0) { pid = fork(); if(pid == 0) { execv("XXX", XXX); } else { // Do something } } return 0; } int main() { start_test(); return 0; } I wants to make first execv execute first than parent creates new

vfork never ends

由 自闭症网瘾萝莉.ら 提交于 2019-12-21 21:49:53
问题 The following code never ends. Why is that? #include <sys/types.h> #include <stdio.h> #include <unistd.h> #define SIZE 5 int nums[SIZE] = {0, 1, 2, 3, 4}; int main() { int i; pid_t pid; pid = vfork(); if(pid == 0){ /* Child process */ for(i = 0; i < SIZE; i++){ nums[i] *= -i; printf(”CHILD: %d “, nums[i]); /* LINE X */ } } else if (pid > 0){ /* Parent process */ wait(NULL); for(i = 0; i < SIZE; i++) printf(”PARENT: %d “, nums[i]); /* LINE Y */ } return 0; } Update: This code is just to

vfork never ends

由 ﹥＞﹥吖頭↗ 提交于 2019-12-04 18:29:01
The following code never ends. Why is that? #include <sys/types.h> #include <stdio.h> #include <unistd.h> #define SIZE 5 int nums[SIZE] = {0, 1, 2, 3, 4}; int main() { int i; pid_t pid; pid = vfork(); if(pid == 0){ /* Child process */ for(i = 0; i < SIZE; i++){ nums[i] *= -i; printf(”CHILD: %d “, nums[i]); /* LINE X */ } } else if (pid > 0){ /* Parent process */ wait(NULL); for(i = 0; i < SIZE; i++) printf(”PARENT: %d “, nums[i]); /* LINE Y */ } return 0; } Update: This code is just to illustrate some of the confusions I have regarding to vfork() . It seems like when I use vfork() , the child

What is the difference between fork() and vfork()?

由 你。 提交于 2019-11-28 08:03:40
What is the difference between fork() and vfork() ? Does vfork() return like fork() . The intent of vfork was to eliminate the overhead of copying the whole process image if you only want to do an exec* in the child. Because exec* replaces the whole image of the child process, there is no point in copying the image of the parent. if ((pid = vfork()) == 0) { execl(..., NULL); /* after a successful execl the parent should be resumed */ _exit(127); /* terminate the child in case execl fails */ } For other kinds of uses, vfork is dangerous and unpredictable. With most current kernels, however,

What is the difference between fork() and vfork()?

由 假如想象 提交于 2019-11-27 02:03:23
问题 What is the difference between fork() and vfork()? Does vfork() return like fork() . 回答1: The intent of vfork was to eliminate the overhead of copying the whole process image if you only want to do an exec* in the child. Because exec* replaces the whole image of the child process, there is no point in copying the image of the parent. if ((pid = vfork()) == 0) { execl(..., NULL); /* after a successful execl the parent should be resumed */ _exit(127); /* terminate the child in case execl fails
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