convert string to argv in c++

c++ stdstring argv
aaronstacy picture aaronstacy · Oct 2, 2009 · Viewed 16.1k times · Source

I have an std::string containing a command to be executed with execv, what is the best "C++" way to convert it to the "char *argv[]" that is required by the second parameter of execv()?

To clarify:

std::string cmd = "mycommand arg1 arg2";
char *cmd_argv[];

StrToArgv(cmd, cmd_argv); // how do I write this function?

execv(cmd_argv[0], cmd_argv);

Answer

Andy Ross picture Andy Ross · Oct 2, 2009

Very non-unixy answers here. What's wrong with:

std::string cmd = "echo hello world";
execl("/bin/sh", "/bin/sh", "-c", cmd.c_str(), NULL);

Why bother writing a command line parser when there's a perfectly good one already on the system?

(Note: one good reason is because you don't trust the string you're about to execute. One hopes that this is already true, but the shell will do "more" with that string than a naive whitespace-splitter will and thus open more security holes if you aren't careful.)

Related questions

std::string formatting like sprintf

I have to format std::string with sprintf and send it into file stream. How can I do this?

Read More
What's the best way to trim std::string?

I'm currently using the following code to right-trim all the std::strings in my programs: std::string s; s.erase(s.find_last_not_of(" \n\r\t")+1); It works fine, but I wonder if there are some end-cases where …

Read More
How to concatenate a std::string and an int?

I thought this would be really simple but it's presenting some difficulties. If I have std::string name = "John"; int age = 21; How do I combine them to get a single string "John21"?

Read More