Ch2-2 Linux多核编程.pdf

Linux 多核编程 南京大学软件学院 Linux 进程 • The entry of C programs • System call “exec ” • System call “fork ” The entry of C programs • crt0.o –cc/ld • main function –function prototype ： int main(int argc, char *argv[]); exec 系列函数的使用 #include unistd.h int execl(const char *path, const char *arg0, ..., (char *)0); int execlp(const char *file, const char *arg0, ..., (char *)0); int execle(const char *path, const char *arg0, ..., (char *)0, char *const envp[]); int execv(const char *path, char *const argv[]); int execvp(const char *file, char *const argv[]); int execve(const char *path, char *const argv[], char *const envp[]); fork 的使用 #include sys/types.h #include unistd.h pid_t fork(void); fork 的使用 if(fork()==0) {子进程执行的代码段；} else {父进程执行的代码段；} The termination of a process • Five ways of terminating a process –Normal termination • Return from ―main‖function • Call ―exit‖function • Call ―_exit‖function • Process with threads：last thread exit –Abnormal termination • Call ―abort‖function • Terminated by a signal • Last thread is cancelled exit _exit functions • Function prototype: #include stdlib.h void exit(int status); #include unistd.h void _exit(int status); • Exit status –How about the status without explicit call？ • Difference –_exit is corresponding to a system call, while ―exit‖ is a library function. –_exit terminate a process immediately. Exit handler • atexit function –Register a function to be called at normal program termination. –Prototype: #include stdlib.h int atexit(void (*function)(void));