CODEWITHSUNDEEP
cbash
sooobus
sooobus

Reputation: 889

C: execlp() and >

I want to run execlp() from C file and write the result to some output file. I use the line:

buff = "./cgi-bin/smth";
execlp(buff, buff, "> /cgi-bin/tmp", NULL);

where smth is a compiled c script. But smth prints to stdout, and no file appears. What happens, and how to put script result to an output file?

Upvotes: 1

Views: 231

Answers (1)

Niklas Rosencrantz
Niklas Rosencrantz

Reputation: 26647

You have to handle it yourself with dup2 if using execlp. You can look at how I handle file out with execvp in comparison. I pass a flag for out redirection and then I handle it:

  if (structpipeline->option[0] == 1) { /* output redirection */    
        int length = structpipeline[i].size;
        char *filename = structpipeline->data[length - 1];
        for (int k = length - 2; k < length; k++)
            structpipeline->data[k] = '\0';    
        fd[1] = open(filename, O_WRONLY | O_CREAT, 0666);
        dup2(fd[1], STDOUT_FILENO);
        close(fd[1]);
    } /* TODO: input redirection */
    execvp(structpipeline[i].data[0], structpipeline[i].data);

See also this question Redirecting exec output to a buffer or file

Upvotes: 1

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