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Conversion between file descriptors and strings
- Pawel Wojciechowski
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Date: | 1997-03-10 (14:32) |
From: | Pawel Wojciechowski <Pawel.Wojciechowski@c...> |
Subject: | Conversion between file descriptors and strings |
Hi all, I just started programming in the Objective Caml language. At the current stage of my project, I need to implement a communication between a process and its child process, which is created by 'fork'. I decided to use pipes from the Unix library. Instead of exchanging standard descriptors (0 and 1) for descriptors fd_in and fd_out created by 'pipe' (as in the expression (fd_out, fd_in) = pipe()), I'd prefer to pass descriptors fd_out and fd_in, to a program executed as a forked process, as arguments when invoking 'execvp'. Then, you can pass these values to the program (which is stored in a separate file and compiled separately) as an array of *strings* being a structural argument to the 'execvp'. My question is how to convert a descriptor of type file_descr into a string and vice-versa? In C, there is no such problems, since descriptors are integers, and you can always write accordingly: sprintf(arg1, "%d", pipe[0]) and descr = atoi(argv[1]) In strongly-typed (O)Caml, we should expect the following error message: "This expression has type int but is here used with type Unix.file_descr" I don't have much experience in using (O)Caml so appologize if you consider that my problem is trivial but please help me sort it out! :) regards, Pawel ps. Pipe is a function from the Unix library and it has types as follows: pipe : init -> file_descr * file_desc