The Bits 2.0

Ever wanted to grab the output of a command via C++?

In PHP, we are all very familiar with @exec and popen, but what about C++?

Try this:

string cmd = "/usr/bin/netstat -na";
string OutString;
FILE *FileStream;
char stdbuffer[1024];
FileStream = popen(cmd.c_str(), "r");
while (fgets(stdbuffer, 1024, FileStream) != NULL)
        OutString.append(stdbuffer);
pclose(FileStream);

• The first 3 lines are variable declarations.
• This is followed by popen command which opens a pipe to the external program. r here means to read from the program output.
• We will now use a 1024 character buffer to read the pipe until a null terminator is encountered.
• Remember to close the process pipe once you’re done!

You ask: “What if I want to have the stderr captured as well?”. No problem! Just add:

2>&1

to the back of your command, just like how you would do it in BASH.