Chapter 25 The unix library: Unix system calls

Chapter 25 The unix library: Unix system calls

The unix library makes many Unixsystem calls and system-related library functions available toOCaml programs. This chapter describes briefly the functionsprovided. Refer to sections 2 and 3 of the Unix manual for moredetails on the behavior of these functions.

Module Unix: Unix system calls
Module UnixLabels: LabeledUnix system callsNot all functions are provided by all Unix variants. If some functionsare not available, they will raise Invalid_arg when called.

Programs that use the unix library must be linked as follows:

        ocamlc other options unix.cma other files
        ocamlopt other options unix.cmxa other files

For interactive use of the unix library, do:

        ocamlmktop -o mytop unix.cma
        ./mytop

or (if dynamic linking of C libraries is supported on your platform),start ocaml and type #load "unix.cma";;.

Windows:A fairly complete emulation of the Unix system calls is provided inthe Windows version of OCaml. The end of this chapter givesmore information on the functions that are not supported under Windows.

Windows:The Cygwin port of OCaml fully implements all functions fromthe Unix module. The native Win32 ports implement a subset of them.Below is a list of the functions that are not implemented, or onlypartially implemented, by the Win32 ports. Functions not mentioned arefully implemented and behave as described previously in this chapter.
Functions Comment
fork not implemented, use create_process or threads
wait not implemented, use waitpid
waitpid can only wait for a given PID, not any child process
getppid not implemented (meaningless under Windows)
nice not implemented
truncate, ftruncate not implemented
link implemented (since 3.02)
symlink, readlink implemented (since 4.03.0)
access execute permission X_OK cannot be tested,it just tests for read permission instead
fchmod not implemented
chown, fchown not implemented (make no sense on a DOSfile system)
umask not implemented
mkfifo not implemented
kill partially implemented (since 4.00.0): only the sigkill signalis implemented
pause not implemented (no inter-process signals in Windows)
alarm not implemented
times partially implemented, will not report timings for childprocesses
getitimer, setitimer not implemented
getuid, geteuid, getgid, getegid always return 1
getgroups always returns [|1|] (since 2.00)
setuid, setgid, setgroups not implemented
getpwnam, getpwuid always raise Not_found
getgrnam, getgrgid always raise Not_found
type socket_domain PF_INET is fully supported;PF_INET6 is fully supported (since 4.01.0); PF_UNIX is not supported
establish_server not implemented; use threads
terminal functions (tc*) not implemented

Functions	Comment
fork	not implemented, use create_process or threads
wait	not implemented, use waitpid
waitpid	can only wait for a given PID, not any child process
getppid	not implemented (meaningless under Windows)
nice	not implemented
truncate, ftruncate	not implemented
link	implemented (since 3.02)
symlink, readlink	implemented (since 4.03.0)
access	execute permission X_OK cannot be tested,it just tests for read permission instead
fchmod	not implemented
chown, fchown	not implemented (make no sense on a DOSfile system)
umask	not implemented
mkfifo	not implemented
kill	partially implemented (since 4.00.0): only the sigkill signalis implemented
pause	not implemented (no inter-process signals in Windows)
alarm	not implemented
times	partially implemented, will not report timings for childprocesses
getitimer, setitimer	not implemented
getuid, geteuid, getgid, getegid	always return 1
getgroups	always returns [\|1\|] (since 2.00)
setuid, setgid, setgroups	not implemented
getpwnam, getpwuid	always raise Not_found
getgrnam, getgrgid	always raise Not_found
type socket_domain	PF_INET is fully supported;PF_INET6 is fully supported (since 4.01.0); PF_UNIX is not supported
establish_server	not implemented; use threads
terminal functions (tc*)	not implemented