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Chapter 24  The unix library: Unix system calls

The unix library makes many Unix system calls and system-related library functions available to OCaml programs. This chapter describes briefly the functions provided. Refer to sections 2 and 3 of the Unix manual for more details on the behavior of these functions.

Not all functions are provided by all Unix variants. If some functions are 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

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 in the Windows version of OCaml. The end of this chapter gives more information on the functions that are not supported under Windows.
Windows:   The Cygwin port of OCaml fully implements all functions from the Unix module. The native Win32 ports implement a subset of them. Below is a list of the functions that are not implemented, or only partially implemented, by the Win32 ports. Functions not mentioned are fully implemented and behave as described previously in this chapter.
forknot implemented, use create_process or threads
waitnot implemented, use waitpid
waitpidcan only wait for a given PID, not any child process
getppidnot implemented (meaningless under Windows)
nicenot implemented
truncate, ftruncatenot implemented
linkimplemented (since 3.02)
symlink, readlinkimplemented (since 4.03.0)
accessexecute permission X_OK cannot be tested, it just tests for read permission instead
fchmodnot implemented
chown, fchownnot implemented (make no sense on a DOS file system)
umasknot implemented
mkfifonot implemented
killpartially implemented (since 4.00.0): only the sigkill signal is implemented
pausenot implemented (no inter-process signals in Windows)
alarmnot implemented
timespartially implemented, will not report timings for child processes
getitimer, setitimernot implemented
getuid, geteuid, getgid, getegidalways return 1
getgroupsalways returns [|1|] (since 2.00)
setuid, setgid, setgroupsnot implemented
getpwnam, getpwuidalways raise Not_found
getgrnam, getgrgidalways raise Not_found
type socket_domainPF_INET is fully supported; PF_INET6 is fully supported (since 4.01.0); PF_UNIX is not supported
establish_servernot implemented; use threads
terminal functions (tc*)not implemented

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