Provided by: libczmq-dev_4.1.0-2_amd64 
NAME
zsys - Class for system-level methods
SYNOPSIS
// This is a stable class, and may not change except for emergencies. It
// is provided in stable builds.
// This class has draft methods, which may change over time. They are not
// in stable releases, by default. Use --enable-drafts to enable.
// Callback for interrupt signal handler
typedef void (zsys_handler_fn) (
int signal_value);
// Initialize CZMQ zsys layer; this happens automatically when you create
// a socket or an actor; however this call lets you force initialization
// earlier, so e.g. logging is properly set-up before you start working.
// Not threadsafe, so call only from main thread. Safe to call multiple
// times. Returns global CZMQ context.
CZMQ_EXPORT void *
zsys_init (void);
// Optionally shut down the CZMQ zsys layer; this normally happens automatically
// when the process exits; however this call lets you force a shutdown
// earlier, avoiding any potential problems with atexit() ordering, especially
// with Windows dlls.
CZMQ_EXPORT void
zsys_shutdown (void);
// Get a new ZMQ socket, automagically creating a ZMQ context if this is
// the first time. Caller is responsible for destroying the ZMQ socket
// before process exits, to avoid a ZMQ deadlock. Note: you should not use
// this method in CZMQ apps, use zsock_new() instead.
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT void *
zsys_socket (int type, const char *filename, size_t line_nbr);
// Destroy/close a ZMQ socket. You should call this for every socket you
// create using zsys_socket().
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT int
zsys_close (void *handle, const char *filename, size_t line_nbr);
// Return ZMQ socket name for socket type
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT char *
zsys_sockname (int socktype);
// Create a pipe, which consists of two PAIR sockets connected over inproc.
// The pipe is configured to use the zsys_pipehwm setting. Returns the
// frontend socket successful, NULL if failed.
CZMQ_EXPORT zsock_t *
zsys_create_pipe (zsock_t **backend_p);
// Set interrupt handler; this saves the default handlers so that a
// zsys_handler_reset () can restore them. If you call this multiple times
// then the last handler will take affect. If handler_fn is NULL, disables
// default SIGINT/SIGTERM handling in CZMQ.
CZMQ_EXPORT void
zsys_handler_set (zsys_handler_fn *handler_fn);
// Reset interrupt handler, call this at exit if needed
CZMQ_EXPORT void
zsys_handler_reset (void);
// Set default interrupt handler, so Ctrl-C or SIGTERM will set
// zsys_interrupted. Idempotent; safe to call multiple times.
// Can be supressed by ZSYS_SIGHANDLER=false
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT void
zsys_catch_interrupts (void);
// Return 1 if file exists, else zero
CZMQ_EXPORT bool
zsys_file_exists (const char *filename);
// Return file modification time. Returns 0 if the file does not exist.
CZMQ_EXPORT time_t
zsys_file_modified (const char *filename);
// Return file mode; provides at least support for the POSIX S_ISREG(m)
// and S_ISDIR(m) macros and the S_IRUSR and S_IWUSR bits, on all boxes.
// Returns a mode_t cast to int, or -1 in case of error.
CZMQ_EXPORT int
zsys_file_mode (const char *filename);
// Delete file. Does not complain if the file is absent
CZMQ_EXPORT int
zsys_file_delete (const char *filename);
// Check if file is 'stable'
CZMQ_EXPORT bool
zsys_file_stable (const char *filename);
// Create a file path if it doesn't exist. The file path is treated as
// printf format.
CZMQ_EXPORT int
zsys_dir_create (const char *pathname, ...);
// Remove a file path if empty; the pathname is treated as printf format.
CZMQ_EXPORT int
zsys_dir_delete (const char *pathname, ...);
// Move to a specified working directory. Returns 0 if OK, -1 if this failed.
CZMQ_EXPORT int
zsys_dir_change (const char *pathname);
// Set private file creation mode; all files created from here will be
// readable/writable by the owner only.
CZMQ_EXPORT void
zsys_file_mode_private (void);
// Reset default file creation mode; all files created from here will use
// process file mode defaults.
CZMQ_EXPORT void
zsys_file_mode_default (void);
// Return the CZMQ version for run-time API detection; returns version
// number into provided fields, providing reference isn't null in each case.
CZMQ_EXPORT void
zsys_version (int *major, int *minor, int *patch);
// Format a string using printf formatting, returning a freshly allocated
// buffer. If there was insufficient memory, returns NULL. Free the returned
// string using zstr_free().
CZMQ_EXPORT char *
zsys_sprintf (const char *format, ...);
// Format a string with a va_list argument, returning a freshly allocated
// buffer. If there was insufficient memory, returns NULL. Free the returned
// string using zstr_free().
CZMQ_EXPORT char *
zsys_vprintf (const char *format, va_list argptr);
// Create UDP beacon socket; if the routable option is true, uses
// multicast (not yet implemented), else uses broadcast. This method
// and related ones might _eventually_ be moved to a zudp class.
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT SOCKET
zsys_udp_new (bool routable);
// Close a UDP socket
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT int
zsys_udp_close (SOCKET handle);
// Send zframe to UDP socket, return -1 if sending failed due to
// interface having disappeared (happens easily with WiFi)
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT int
zsys_udp_send (SOCKET udpsock, zframe_t *frame, inaddr_t *address, int addrlen);
// Receive zframe from UDP socket, and set address of peer that sent it
// The peername must be a char [INET_ADDRSTRLEN] array if IPv6 is disabled or
// NI_MAXHOST if it's enabled. Returns NULL when failing to get peer address.
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT zframe_t *
zsys_udp_recv (SOCKET udpsock, char *peername, int peerlen);
// Handle an I/O error on some socket operation; will report and die on
// fatal errors, and continue silently on "try again" errors.
// *** This is for CZMQ internal use only and may change arbitrarily ***
CZMQ_EXPORT void
zsys_socket_error (const char *reason);
// Return current host name, for use in public tcp:// endpoints. Caller gets
// a freshly allocated string, should free it using zstr_free(). If the host
// name is not resolvable, returns NULL.
CZMQ_EXPORT char *
zsys_hostname (void);
// Move the current process into the background. The precise effect depends
// on the operating system. On POSIX boxes, moves to a specified working
// directory (if specified), closes all file handles, reopens stdin, stdout,
// and stderr to the null device, and sets the process to ignore SIGHUP. On
// Windows, does nothing. Returns 0 if OK, -1 if there was an error.
CZMQ_EXPORT int
zsys_daemonize (const char *workdir);
// Drop the process ID into the lockfile, with exclusive lock, and switch
// the process to the specified group and/or user. Any of the arguments
// may be null, indicating a no-op. Returns 0 on success, -1 on failure.
// Note if you combine this with zsys_daemonize, run after, not before
// that method, or the lockfile will hold the wrong process ID.
CZMQ_EXPORT int
zsys_run_as (const char *lockfile, const char *group, const char *user);
// Returns true if the underlying libzmq supports CURVE security.
// Uses a heuristic probe according to the version of libzmq being used.
CZMQ_EXPORT bool
zsys_has_curve (void);
// Configure the number of I/O threads that ZeroMQ will use. A good
// rule of thumb is one thread per gigabit of traffic in or out. The
// default is 1, sufficient for most applications. If the environment
// variable ZSYS_IO_THREADS is defined, that provides the default.
// Note that this method is valid only before any socket is created.
CZMQ_EXPORT void
zsys_set_io_threads (size_t io_threads);
// Configure the scheduling policy of the ZMQ context thread pool.
// Not available on Windows. See the sched_setscheduler man page or sched.h
// for more information. If the environment variable ZSYS_THREAD_SCHED_POLICY
// is defined, that provides the default.
// Note that this method is valid only before any socket is created.
CZMQ_EXPORT void
zsys_set_thread_sched_policy (int policy);
// Configure the scheduling priority of the ZMQ context thread pool.
// Not available on Windows. See the sched_setscheduler man page or sched.h
// for more information. If the environment variable ZSYS_THREAD_PRIORITY is
// defined, that provides the default.
// Note that this method is valid only before any socket is created.
CZMQ_EXPORT void
zsys_set_thread_priority (int priority);
// Configure the number of sockets that ZeroMQ will allow. The default
// is 1024. The actual limit depends on the system, and you can query it
// by using zsys_socket_limit (). A value of zero means "maximum".
// Note that this method is valid only before any socket is created.
CZMQ_EXPORT void
zsys_set_max_sockets (size_t max_sockets);
// Return maximum number of ZeroMQ sockets that the system will support.
CZMQ_EXPORT size_t
zsys_socket_limit (void);
// Configure the maximum allowed size of a message sent.
// The default is INT_MAX.
CZMQ_EXPORT void
zsys_set_max_msgsz (int max_msgsz);
// Return maximum message size.
CZMQ_EXPORT int
zsys_max_msgsz (void);
// Configure the default linger timeout in msecs for new zsock instances.
// You can also set this separately on each zsock_t instance. The default
// linger time is zero, i.e. any pending messages will be dropped. If the
// environment variable ZSYS_LINGER is defined, that provides the default.
// Note that process exit will typically be delayed by the linger time.
CZMQ_EXPORT void
zsys_set_linger (size_t linger);
// Configure the default outgoing pipe limit (HWM) for new zsock instances.
// You can also set this separately on each zsock_t instance. The default
// HWM is 1,000, on all versions of ZeroMQ. If the environment variable
// ZSYS_SNDHWM is defined, that provides the default. Note that a value of
// zero means no limit, i.e. infinite memory consumption.
CZMQ_EXPORT void
zsys_set_sndhwm (size_t sndhwm);
// Configure the default incoming pipe limit (HWM) for new zsock instances.
// You can also set this separately on each zsock_t instance. The default
// HWM is 1,000, on all versions of ZeroMQ. If the environment variable
// ZSYS_RCVHWM is defined, that provides the default. Note that a value of
// zero means no limit, i.e. infinite memory consumption.
CZMQ_EXPORT void
zsys_set_rcvhwm (size_t rcvhwm);
// Configure the default HWM for zactor internal pipes; this is set on both
// ends of the pipe, for outgoing messages only (sndhwm). The default HWM is
// 1,000, on all versions of ZeroMQ. If the environment var ZSYS_ACTORHWM is
// defined, that provides the default. Note that a value of zero means no
// limit, i.e. infinite memory consumption.
CZMQ_EXPORT void
zsys_set_pipehwm (size_t pipehwm);
// Return the HWM for zactor internal pipes.
CZMQ_EXPORT size_t
zsys_pipehwm (void);
// Configure use of IPv6 for new zsock instances. By default sockets accept
// and make only IPv4 connections. When you enable IPv6, sockets will accept
// and connect to both IPv4 and IPv6 peers. You can override the setting on
// each zsock_t instance. The default is IPv4 only (ipv6 set to 0). If the
// environment variable ZSYS_IPV6 is defined (as 1 or 0), this provides the
// default. Note: has no effect on ZMQ v2.
CZMQ_EXPORT void
zsys_set_ipv6 (int ipv6);
// Return use of IPv6 for zsock instances.
CZMQ_EXPORT int
zsys_ipv6 (void);
// Set network interface name to use for broadcasts, particularly zbeacon.
// This lets the interface be configured for test environments where required.
// For example, on Mac OS X, zbeacon cannot bind to 255.255.255.255 which is
// the default when there is no specified interface. If the environment
// variable ZSYS_INTERFACE is set, use that as the default interface name.
// Setting the interface to "*" means "use all available interfaces".
CZMQ_EXPORT void
zsys_set_interface (const char *value);
// Return network interface to use for broadcasts, or "" if none was set.
CZMQ_EXPORT const char *
zsys_interface (void);
// Set IPv6 address to use zbeacon socket, particularly for receiving zbeacon.
// This needs to be set IPv6 is enabled as IPv6 can have multiple addresses
// on a given interface. If the environment variable ZSYS_IPV6_ADDRESS is set,
// use that as the default IPv6 address.
CZMQ_EXPORT void
zsys_set_ipv6_address (const char *value);
// Return IPv6 address to use for zbeacon reception, or "" if none was set.
CZMQ_EXPORT const char *
zsys_ipv6_address (void);
// Set IPv6 milticast address to use for sending zbeacon messages. This needs
// to be set if IPv6 is enabled. If the environment variable
// ZSYS_IPV6_MCAST_ADDRESS is set, use that as the default IPv6 multicast
// address.
CZMQ_EXPORT void
zsys_set_ipv6_mcast_address (const char *value);
// Return IPv6 multicast address to use for sending zbeacon, or "" if none was
// set.
CZMQ_EXPORT const char *
zsys_ipv6_mcast_address (void);
// Configure the automatic use of pre-allocated FDs when creating new sockets.
// If 0 (default), nothing will happen. Else, when a new socket is bound, the
// system API will be used to check if an existing pre-allocated FD with a
// matching port (if TCP) or path (if IPC) exists, and if it does it will be
// set via the ZMQ_USE_FD socket option so that the library will use it
// instead of creating a new socket.
CZMQ_EXPORT void
zsys_set_auto_use_fd (int auto_use_fd);
// Return use of automatic pre-allocated FDs for zsock instances.
CZMQ_EXPORT int
zsys_auto_use_fd (void);
// Set log identity, which is a string that prefixes all log messages sent
// by this process. The log identity defaults to the environment variable
// ZSYS_LOGIDENT, if that is set.
CZMQ_EXPORT void
zsys_set_logident (const char *value);
// Set stream to receive log traffic. By default, log traffic is sent to
// stdout. If you set the stream to NULL, no stream will receive the log
// traffic (it may still be sent to the system facility).
CZMQ_EXPORT void
zsys_set_logstream (FILE *stream);
// Sends log output to a PUB socket bound to the specified endpoint. To
// collect such log output, create a SUB socket, subscribe to the traffic
// you care about, and connect to the endpoint. Log traffic is sent as a
// single string frame, in the same format as when sent to stdout. The
// log system supports a single sender; multiple calls to this method will
// bind the same sender to multiple endpoints. To disable the sender, call
// this method with a null argument.
CZMQ_EXPORT void
zsys_set_logsender (const char *endpoint);
// Enable or disable logging to the system facility (syslog on POSIX boxes,
// event log on Windows). By default this is disabled.
CZMQ_EXPORT void
zsys_set_logsystem (bool logsystem);
// Log error condition - highest priority
CZMQ_EXPORT void
zsys_error (const char *format, ...);
// Log warning condition - high priority
CZMQ_EXPORT void
zsys_warning (const char *format, ...);
// Log normal, but significant, condition - normal priority
CZMQ_EXPORT void
zsys_notice (const char *format, ...);
// Log informational message - low priority
CZMQ_EXPORT void
zsys_info (const char *format, ...);
// Log debug-level message - lowest priority
CZMQ_EXPORT void
zsys_debug (const char *format, ...);
// Self test of this class.
CZMQ_EXPORT void
zsys_test (bool verbose);
#ifdef CZMQ_BUILD_DRAFT_API
// *** Draft method, for development use, may change without warning ***
// Configure the threshold value of filesystem object age per st_mtime
// that should elapse until we consider that object "stable" at the
// current zclock_time() moment.
// The default is S_DEFAULT_ZSYS_FILE_STABLE_AGE_MSEC defined in zsys.c
// which generally depends on host OS, with fallback value of 5000.
CZMQ_EXPORT void
zsys_set_file_stable_age_msec (int64_t file_stable_age_msec);
// *** Draft method, for development use, may change without warning ***
// Return current threshold value of file stable age in msec.
// This can be used in code that chooses to wait for this timeout
// before testing if a filesystem object is "stable" or not.
CZMQ_EXPORT int64_t
zsys_file_stable_age_msec (void);
#endif // CZMQ_BUILD_DRAFT_API
Please add '@interface' section in './../src/zsys.c'.
DESCRIPTION
The zsys class provides a portable wrapper for system calls. We collect them here to
reduce the number of weird #ifdefs in other classes. As far as possible, the bulk of CZMQ
classes are fully portable.
Please add @discuss section in ./../src/zsys.c.
EXAMPLE
From zsys_test method.
zsys_catch_interrupts ();
// Check capabilities without using the return value
int rc = zsys_has_curve ();
const char *SELFTEST_DIR_RW = "src/selftest-rw";
if (verbose) {
char *hostname = zsys_hostname ();
zsys_info ("host name is %s", hostname);
freen (hostname);
zsys_info ("system limit is %zu ZeroMQ sockets", zsys_socket_limit ());
}
zsys_set_file_stable_age_msec (5123);
assert (zsys_file_stable_age_msec() == 5123);
zsys_set_file_stable_age_msec (-1);
assert (zsys_file_stable_age_msec() == 5123);
zsys_set_linger (0);
zsys_set_sndhwm (1000);
zsys_set_rcvhwm (1000);
zsys_set_pipehwm (2500);
assert (zsys_pipehwm () == 2500);
zsys_set_ipv6 (0);
zsys_set_thread_priority (-1);
zsys_set_thread_sched_policy (-1);
// Test pipe creation
zsock_t *pipe_back;
zsock_t *pipe_front = zsys_create_pipe (&pipe_back);
zstr_send (pipe_front, "Hello");
char *string = zstr_recv (pipe_back);
assert (streq (string, "Hello"));
freen (string);
zsock_destroy (&pipe_back);
zsock_destroy (&pipe_front);
// Test file manipulation
// Don't let anyone fool our workspace
if (zsys_file_exists ("nosuchfile")) {
zsys_warning ("zsys_test() had to remove 'nosuchfile' which was not expected here at all");
zsys_file_delete ("nosuchfile");
}
rc = zsys_file_delete ("nosuchfile");
assert (rc == -1);
bool rc_bool = zsys_file_exists ("nosuchfile");
assert (rc_bool != true);
rc = (int) zsys_file_size ("nosuchfile");
assert (rc == -1);
time_t when = zsys_file_modified (".");
assert (when > 0);
int mode = zsys_file_mode (".");
assert (S_ISDIR (mode));
assert (mode & S_IRUSR);
assert (mode & S_IWUSR);
const char *testbasedir = ".testsys";
const char *testsubdir = "subdir";
char *basedirpath = NULL; // subdir in a test, under SELFTEST_DIR_RW
char *dirpath = NULL; // subdir in a test, under basedirpath
char *relsubdir = NULL; // relative short "path" of subdir under testbasedir
basedirpath = zsys_sprintf ("%s/%s", SELFTEST_DIR_RW, testbasedir);
assert (basedirpath);
dirpath = zsys_sprintf ("%s/%s", basedirpath, testsubdir);
assert (dirpath);
relsubdir = zsys_sprintf ("%s/%s", testbasedir, testsubdir);
assert (relsubdir);
// Normally tests clean up in the end, but if a selftest run dies
// e.g. on assert(), workspace remains dirty. Better clean it up.
// We do not really care about results here - we clean up a possible
// dirty exit of an older build. If there are permission errors etc.
// the actual tests below would explode.
if (zsys_file_exists(dirpath)) {
if (verbose)
zsys_debug ("zsys_test() has to remove ./%s that should not have been here", dirpath);
zsys_dir_delete (dirpath);
}
if (zsys_file_exists (basedirpath)) {
if (verbose)
zsys_debug ("zsys_test() has to remove ./%s that should not have been here", basedirpath);
zsys_dir_delete (basedirpath);
}
// Added tracing because this file-age check fails on some systems
// presumably due to congestion in a mass-build and valgrind on top
zsys_file_mode_private ();
if (verbose)
printf ("zsys_test() at timestamp %" PRIi64 ": "
"Creating %s\n",
zclock_time(), relsubdir );
rc = zsys_dir_create ("%s/%s", SELFTEST_DIR_RW, relsubdir);
if (verbose)
printf ("zsys_test() at timestamp %" PRIi64 ": "
"Finished creating %s with return-code %d\n",
zclock_time(), relsubdir, rc );
assert (rc == 0);
when = zsys_file_modified (dirpath);
if (verbose)
printf ("zsys_test() at timestamp %" PRIi64 ": "
"Finished calling zsys_file_modified(), got age %jd\n",
zclock_time(), (intmax_t)when );
assert (when > 0);
if (verbose)
printf ("zsys_test() at timestamp %" PRIi64 ": "
"Checking if file is NOT stable (is younger than 1 sec)\n",
zclock_time() );
assert (!s_zsys_file_stable (dirpath, verbose));
if (verbose)
printf ("zsys_test() at timestamp %" PRIi64 ": "
"Passed the test, file is not stable - as expected\n",
zclock_time() );
rc = zsys_dir_delete ("%s/%s", SELFTEST_DIR_RW, relsubdir);
assert (rc == 0);
rc = zsys_dir_delete ("%s/%s", SELFTEST_DIR_RW, testbasedir);
assert (rc == 0);
zsys_file_mode_default ();
#if (defined (PATH_MAX))
char cwd[PATH_MAX];
#else
# if (defined (_MAX_PATH))
char cwd[_MAX_PATH];
# else
char cwd[1024];
# endif
#endif
memset (cwd, 0, sizeof(cwd));
#if (defined (WIN32))
if (_getcwd(cwd, sizeof(cwd)) != NULL) {
#else
if (getcwd(cwd, sizeof(cwd)) != NULL) {
#endif
if (verbose)
printf ("zsys_test() at timestamp %" PRIi64 ": "
"current working directory is %s\n",
zclock_time(), cwd);
assert (zsys_dir_change (SELFTEST_DIR_RW) == 0);
assert (zsys_dir_change (cwd) == 0);
}
else {
zsys_warning ("zsys_test() : got getcwd() error... "
"testing zsys_dir_change() anyway, but it can confuse "
"subsequent tests in this process");
assert (zsys_dir_change (SELFTEST_DIR_RW) == 0);
}
zstr_free (&basedirpath);
zstr_free (&dirpath);
zstr_free (&relsubdir);
// Other subtests
int major, minor, patch;
zsys_version (&major, &minor, &patch);
assert (major == CZMQ_VERSION_MAJOR);
assert (minor == CZMQ_VERSION_MINOR);
assert (patch == CZMQ_VERSION_PATCH);
string = zsys_sprintf ("%s %02x", "Hello", 16);
assert (streq (string, "Hello 10"));
freen (string);
char *str64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890,.";
int num10 = 1234567890;
string = zsys_sprintf ("%s%s%s%s%d", str64, str64, str64, str64, num10);
assert (strlen (string) == (4 * 64 + 10));
freen (string);
// Test logging system
zsys_set_logident ("czmq_selftest");
zsys_set_logsender ("inproc://logging");
void *logger = zsys_socket (ZMQ_SUB, NULL, 0);
assert (logger);
rc = zmq_connect (logger, "inproc://logging");
assert (rc == 0);
rc = zmq_setsockopt (logger, ZMQ_SUBSCRIBE, "", 0);
assert (rc == 0);
if (verbose) {
zsys_error ("This is an %s message", "error");
zsys_warning ("This is a %s message", "warning");
zsys_notice ("This is a %s message", "notice");
zsys_info ("This is a %s message", "info");
zsys_debug ("This is a %s message", "debug");
zsys_set_logident ("hello, world");
zsys_info ("This is a %s message", "info");
zsys_debug ("This is a %s message", "debug");
// Check that logsender functionality is working
char *received = zstr_recv (logger);
assert (received);
zstr_free (&received);
}
zsys_close (logger, NULL, 0);
AUTHORS
The czmq manual was written by the authors in the AUTHORS file.
RESOURCES
Main web site:
Report bugs to the email <zeromq-dev@lists.zeromq.org[1]>
COPYRIGHT
Copyright (c) the Contributors as noted in the AUTHORS file. This file is part of CZMQ,
the high-level C binding for 0MQ: http://czmq.zeromq.org. This Source Code Form is subject
to the terms of the Mozilla Public License, v. 2.0. If a copy of the MPL was not
distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/. LICENSE
included with the czmq distribution.
NOTES
1. zeromq-dev@lists.zeromq.org
mailto:zeromq-dev@lists.zeromq.org