I am trying to understand a program here I have not been able to understand the static int split(char *cmd_exec, int input, int first, int last) function what is the purpose of int input,int first,int last here , this function returns return command(input, first, last, new_cmd_exec1); what does input,first,last and new_cmd_exec1 signify here? Why do we need to spilt the commands passed on to a shell ? The relevant code is following
我试图理解一个程序在这里我无法理解静态int split（char * cmd_exec，int input，int first，int last）函数int输入的目的是什么，int first，int last here，this function返回return命令（input，first，last，new_cmd_exec1）; input，first，last和new_cmd_exec1在这里表示什么？为什么我们需要将传递给shell的命令溢出？相关代码如下
static int split(char *cmd_exec, int input, int first, int last)
{
char *new_cmd_exec1;
new_cmd_exec1=strdup(cmd_exec);
//else
{
int m=1;
args[0]=strtok(cmd_exec," ");
while((args[m]=strtok(NULL," "))!=NULL)
m++;
args[m]=NULL;
if (args[0] != NULL)
{
if (strcmp(args[0], "exit") == 0)
exit(0);
if (strcmp(args[0], "echo") != 0)
{
cmd_exec = skipcomma(new_cmd_exec1);
int m=1;
args[0]=strtok(cmd_exec," ");
while((args[m]=strtok(NULL," "))!=NULL)
m++;
args[m]=NULL;
}
if(strcmp("cd",args[0])==0)
{
change_directory();
return 1;
}
else if(strcmp("pwd",args[0])==0)
{
parent_directory();
return 1;
}
}
}
return command(input, first, last, new_cmd_exec1);
}
1 个解决方案
#1
0
The meaning of the variables isn't clear from the code you posted. However, if you can find any documentation for, or the definition of, the function command(), you may be able to learn their intended purpose.
从您发布的代码中不清楚变量的含义。但是，如果您可以找到函数command（）的任何文档或定义，您可以了解它们的预期用途。
Having said that, it's pretty clear from the code that these parameters are just copies of the parameters that were initially passed to split() and passed on to command(), so it is likely that the integers are general purpose parameters whose meaning will depend on the eventual type of command executed.
话虽如此，从代码中可以清楚地看出，这些参数只是最初传递给split（）并传递给command（）的参数的副本，因此整数很可能是通用参数，其含义取决于关于最终执行的命令类型。
#1
0
The meaning of the variables isn't clear from the code you posted. However, if you can find any documentation for, or the definition of, the function command(), you may be able to learn their intended purpose.
从您发布的代码中不清楚变量的含义。但是，如果您可以找到函数command（）的任何文档或定义，您可以了解它们的预期用途。
Having said that, it's pretty clear from the code that these parameters are just copies of the parameters that were initially passed to split() and passed on to command(), so it is likely that the integers are general purpose parameters whose meaning will depend on the eventual type of command executed.
话虽如此，从代码中可以清楚地看出，这些参数只是最初传递给split（）并传递给command（）的参数的副本，因此整数很可能是通用参数，其含义取决于关于最终执行的命令类型。