使用posix_spawn启动进程 [英] Starting a process using posix_spawn

问题描述

我正在使用以下代码在Linux中启动新进程

i am using the folowing code to launch the new process in Linux

pid_t processID;
char *argV[] = {"192.168.1.40",(char *) 0};
int status = -1;
status = posix_spawn(&processID,"/home/user/application",NULL,NULL,argV,environ);
if(status == 0)
     std::cout<<"Launched Application";
else
     std::cout<<"Launching application Failed";

应用程序确实启动，但是没有命令行参数. posix_spawn参数有什么错误?

Application did launches but says no command line argument. What is the error in posix_spawn arguments?

推荐答案

在posix_spawn手册页中:

自变量argv是指向以null终止的字符数组的指针，该数组指向以null终止的字符串.这些字符串构成参数列表以供新进程使用.数组中至少必须存在argv [0]，并且应包含要生成的程序的文件名，例如路径或文件参数的最后一个组成部分.

The argument argv is a pointer to a null-terminated array of character pointers to null-terminated character strings. These strings construct the argument list to be made available to the new process. At least argv[0] must be present in the array, and should contain the file name of the program being spawned, e.g. the last component of the path or file argument.

正在发生的是，在启动的过程中，argv[0]将是192.168.1.40而不是可执行文件的名称，并且此后没有程序的参数.

What's happening is that in the launched process, argv[0] will be 192.168.1.40 instead of the name of the executable, and there are no arguments to the program after that.

所以改变:

 char *argV[] = {"192.168.1.40",(char *) 0};

收件人:

char *argV[] = {"/home/user/application", "192.168.1.40",(char *) 0};

稍后将更明确地提及argv数组的行为:

The behaviour of the argv array is mentioned more explicitly later on:

当通过posix_spawn()或posix_spawnp()调用执行程序时，其输入如下:

When a program is executed as a result of a posix_spawn() or posix_spawnp() call, it is entered as follows:

main(argc, argv, envp)
int argc;
char **argv, **envp;

其中argc是argv中的元素数("arg计数")，而argv指向指向参数本身的字符指针数组.

where argc is the number of elements in argv (the ''arg count'') and argv points to the array of character pointers to the arguments themselves.

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