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Change the current working directory to str. The return value is unspecified.
Return the name of the current working directory.
If mode is omitted, returns a decimal number representing the current file creation mask. Otherwise the file creation mask is set to mode and the previous value is returned. See Assigning File Permissions in The GNU C Library Reference Manual, for more on how to use umasks.
E.g., (umask #o022) sets the mask to octal 22/decimal 18.
Change the root directory to that specified in path. This directory will be used for path names beginning with /. The root directory is inherited by all children of the current process. Only the superuser may change the root directory.
Return an integer representing the current process ID.
Return a vector of integers representing the current supplementary group IDs.
Return an integer representing the process ID of the parent process.
Return an integer representing the current real user ID.
Return an integer representing the current real group ID.
Return an integer representing the current effective user ID.
If the system does not support effective IDs, then the real ID
is returned. (provided? 'EIDs) reports whether the
system supports effective IDs.
Return an integer representing the current effective group ID.
If the system does not support effective IDs, then the real ID
is returned. (provided? 'EIDs) reports whether the
system supports effective IDs.
Set the current set of supplementary group IDs to the integers in the given vector vec. The return value is unspecified.
Generally only the superuser can set the process group IDs (see Setting the Group IDs in The GNU C Library Reference Manual).
Sets both the real and effective user IDs to the integer id, provided the process has appropriate privileges. The return value is unspecified.
Sets both the real and effective group IDs to the integer id, provided the process has appropriate privileges. The return value is unspecified.
Sets the effective user ID to the integer id, provided the process
has appropriate privileges. If effective IDs are not supported, the
real ID is set instead—(provided? 'EIDs) reports whether the
system supports effective IDs.
The return value is unspecified.
Sets the effective group ID to the integer id, provided the process
has appropriate privileges. If effective IDs are not supported, the
real ID is set instead—(provided? 'EIDs) reports whether the
system supports effective IDs.
The return value is unspecified.
Return an integer representing the current process group ID. This is the POSIX definition, not BSD.
Move the process pid into the process group pgid. pid or pgid must be integers: they can be zero to indicate the ID of the current process. Fails on systems that do not support job control. The return value is unspecified.
Creates a new session. The current process becomes the session leader and is put in a new process group. The process will be detached from its controlling terminal if it has one. The return value is an integer representing the new process group ID.
Returns the session ID of process pid. (The session ID of a process is the process group ID of its session leader.)
This procedure collects status information from a child process which has terminated or (optionally) stopped. Normally it will suspend the calling process until this can be done. If more than one child process is eligible then one will be chosen by the operating system.
The value of pid determines the behaviour:
Request status information from the specified child process.
WAIT_ANYRequest status information for any child process.
WAIT_MYPGRPRequest status information for any child process in the current process group.
Request status information for any child process whose process group ID is -pid.
The options argument, if supplied, should be the bitwise OR of the values of zero or more of the following variables:
Return immediately even if there are no child processes to be collected.
Report status information for stopped processes as well as terminated processes.
The return value is a pair containing:
WNOHANG was
specified and no process was collected.
The following three
functions can be used to decode the integer status value returned by
waitpid.
Return the exit status value, as would be set if a process
ended normally through a call to exit or _exit,
if any, otherwise #f.
Return the signal number which terminated the process, if any,
otherwise #f.
Return the signal number which stopped the process, if any,
otherwise #f.
Execute cmd using the operating system’s “command
processor”. Under Unix this is usually the default shell
sh. The value returned is cmd’s exit status as
returned by waitpid, which can be interpreted using the
functions above.
If system is called without arguments, return a boolean
indicating whether the command processor is available.
Execute the command indicated by arg1 arg2 .... The first element must be a string indicating the command to be executed, and the remaining items must be strings representing each of the arguments to that command.
This function returns the exit status of the command as provided by
waitpid. This value can be handled with status:exit-val
and the related functions.
system* is similar to system, but accepts only one
string per-argument, and performs no shell interpretation. The
command is executed using fork and execlp. Accordingly this function
may be safer than system in situations where shell
interpretation is not required.
Example: (system* "echo" "foo" "bar")
Terminate the current process with proper unwinding of the Scheme stack.
The exit status zero if status is not supplied. If status
is supplied, and it is an integer, that integer is used as the exit
status. If status is #t or #f, the exit status is
EXIT_SUCCESS or EXIT_FAILURE, respectively.
The procedure exit is an alias of quit. They have the
same functionality.
These constants represent the standard exit codes for success (zero) or failure (one.)
Terminate the current process without unwinding the Scheme stack. The exit status is status if supplied, otherwise zero.
primitive-exit uses the C exit function and hence runs
usual C level cleanups (flush output streams, call atexit
functions, etc, see Normal Termination in The GNU C Library
Reference Manual)).
primitive-_exit is the _exit system call
(see Termination Internals in The GNU C Library Reference
Manual). This terminates the program immediately, with neither
Scheme-level nor C-level cleanups.
The typical use for primitive-_exit is from a child process
created with primitive-fork. For example in a Gdk program the
child process inherits the X server connection and a C-level
atexit cleanup which will close that connection. But closing
in the child would upset the protocol in the parent, so
primitive-_exit should be used to exit without that.
Executes the file named by filename as a new process image.
The remaining arguments are supplied to the process; from a C program
they are accessible as the argv argument to main.
Conventionally the first arg is the same as filename.
All arguments must be strings.
If arg is missing, filename is executed with a null argument list, which may have system-dependent side-effects.
This procedure is currently implemented using the execv system
call, but we call it execl because of its Scheme calling interface.
Similar to execl, however if
filename does not contain a slash
then the file to execute will be located by searching the
directories listed in the PATH environment variable.
This procedure is currently implemented using the execvp system
call, but we call it execlp because of its Scheme calling interface.
Similar to execl, but the environment of the new process is
specified by env, which must be a list of strings as returned by the
environ procedure.
This procedure is currently implemented using the execve system
call, but we call it execle because of its Scheme calling interface.
Creates a new “child” process by duplicating the current “parent” process. In the child the return value is 0. In the parent the return value is the integer process ID of the child.
Note that it is unsafe to fork a process that has multiple threads
running, as only the thread that calls primitive-fork will
persist in the child. Any resources that other threads held, such as
locked mutexes or open file descriptors, are lost. Indeed,
POSIX specifies that only async-signal-safe procedures are
safe to call after a multithreaded fork, which is a very limited set.
Guile issues a warning if it detects a fork from a multi-threaded
program.
If you are going to exec soon after forking, the procedures in
(ice-9 popen) may be useful to you, as they fork and exec within
an async-signal-safe function carefully written to ensure robust program
behavior, even in the presence of threads. See Pipes, for more.
This procedure has been renamed from fork to avoid a naming conflict
with the scsh fork.
Increment the priority of the current process by incr. A higher priority value means that the process runs less often. The return value is unspecified.
Set the scheduling priority of the process, process group
or user, as indicated by which and who. which
is one of the variables PRIO_PROCESS, PRIO_PGRP
or PRIO_USER, and who is interpreted relative to
which (a process identifier for PRIO_PROCESS,
process group identifier for PRIO_PGRP, and a user
identifier for PRIO_USER. A zero value of who
denotes the current process, process group, or user.
prio is a value in the range [-20,20]. The default
priority is 0; lower priorities (in numerical terms) cause more
favorable scheduling. Sets the priority of all of the specified
processes. Only the super-user may lower priorities. The return
value is not specified.
Return the scheduling priority of the process, process group
or user, as indicated by which and who. which
is one of the variables PRIO_PROCESS, PRIO_PGRP
or PRIO_USER, and who should be interpreted depending on
which (a process identifier for PRIO_PROCESS,
process group identifier for PRIO_PGRP, and a user
identifier for PRIO_USER). A zero value of who
denotes the current process, process group, or user. Return
the highest priority (lowest numerical value) of any of the
specified processes.
Return a bitvector representing the CPU affinity mask for process pid. Each CPU the process has affinity with has its corresponding bit set in the returned bitvector. The number of bits set is a good estimate of how many CPUs Guile can use without stepping on other processes’ toes.
Currently this procedure is only defined on GNU variants
(see sched_getaffinity in The
GNU C Library Reference Manual).
Install the CPU affinity mask mask, a bitvector, for the process or thread with ID pid. The return value is unspecified.
Currently this procedure is only defined on GNU variants
(see sched_setaffinity in The
GNU C Library Reference Manual).
See Threads, for information on how get the number of processors available on a system.
Next: Signals, Previous: Runtime Environment, Up: POSIX [Contents][Index]