Provided by: libczmq-dev_4.2.1-2build1_amd64 bug

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 suppressed 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 numeric prefix to each thread created for the internal
       //  context's thread pool. This option is only supported on Linux.
       //  If the environment variable ZSYS_THREAD_NAME_PREFIX is defined, that
       //  provides the default.
       //  Note that this method is valid only before any socket is created.
       CZMQ_EXPORT void
           zsys_set_thread_name_prefix (int prefix);

       //  Return thread name prefix.
       CZMQ_EXPORT int
           zsys_thread_name_prefix (void);

       //  Adds a specific CPU to the affinity list of the ZMQ context thread pool.
       //  This option is only supported on Linux.
       //  Note that this method is valid only before any socket is created.
       CZMQ_EXPORT void
           zsys_thread_affinity_cpu_add (int cpu);

       //  Removes a specific CPU to the affinity list of the ZMQ context thread pool.
       //  This option is only supported on Linux.
       //  Note that this method is valid only before any socket is created.
       CZMQ_EXPORT void
           zsys_thread_affinity_cpu_remove (int cpu);

       //  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 ***
       //  Check if default interrupt handler of Ctrl-C or SIGTERM was called.
       //  Does not work if ZSYS_SIGHANDLER is false and code does not call
       //  set interrupted on signal.
       CZMQ_EXPORT bool
           zsys_is_interrupted (void);

       //  *** Draft method, for development use, may change without warning ***
       //  Set interrupted flag. This is done by default signal handler, however
       //  this can be handy for language bindings or cases without default
       //  signal handler.
       CZMQ_EXPORT void
           zsys_set_interrupted (void);

       //  *** Draft method, for development use, may change without warning ***
       //  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(). The hinted version allows to optimize by using
       //  a larger starting buffer size (known to/assumed by the developer) and so
       //  avoid reallocations.
       CZMQ_EXPORT char *
           zsys_sprintf_hint (int hint, const char *format, ...);

       //  *** Draft method, for development use, may change without warning ***
       //  Configure the numeric prefix to each thread created for the internal
       //  context's thread pool. This option is only supported on Linux.
       //  If the environment variable ZSYS_THREAD_NAME_PREFIX_STR is defined, that
       //  provides the default.
       //  Note that this method is valid only before any socket is created.
       CZMQ_EXPORT void
           zsys_set_thread_name_prefix_str (const char *prefix);

       //  *** Draft method, for development use, may change without warning ***
       //  Return thread name prefix.
       CZMQ_EXPORT const char *
           zsys_thread_name_prefix_str (void);

       //  *** Draft method, for development use, may change without warning ***
       //  Configure whether to use zero copy strategy in libzmq. If the environment
       //  variable ZSYS_ZERO_COPY_RECV is defined, that provides the default.
       //  Otherwise the default is 1.
       CZMQ_EXPORT void
           zsys_set_zero_copy_recv (int zero_copy);

       //  *** Draft method, for development use, may change without warning ***
       //  Return ZMQ_ZERO_COPY_RECV option.
       CZMQ_EXPORT int
           zsys_zero_copy_recv (void);

       //  *** 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);

       //  *** Draft method, for development use, may change without warning ***
       //  Test if ipv6 is available on the system. Return true if available.
       //  The only way to reliably check is to actually open a socket and
       //  try to bind it. (ported from libzmq)
       CZMQ_EXPORT bool
           zsys_ipv6_available (void);

       //  *** Draft method, for development use, may change without warning ***
       //  Set IPv4 multicast address to use for sending zbeacon messages. By default
       //  IPv4 multicast is NOT used. If the environment variable
       //  ZSYS_IPV4_MCAST_ADDRESS is set, use that as the default IPv4 multicast
       //  address. Calling this function or setting ZSYS_IPV4_MCAST_ADDRESS
       //  will enable IPv4 zbeacon messages.
       CZMQ_EXPORT void
           zsys_set_ipv4_mcast_address (const char *value);

       //  *** Draft method, for development use, may change without warning ***
       //  Return IPv4 multicast address to use for sending zbeacon, or NULL if none was
       //  set.
       CZMQ_EXPORT const char *
           zsys_ipv4_mcast_address (void);

       //  *** Draft method, for development use, may change without warning ***
       //  Set multicast TTL default is 1
       CZMQ_EXPORT void
           zsys_set_mcast_ttl (byte value);

       //  *** Draft method, for development use, may change without warning ***
       //  Get multicast TTL
       CZMQ_EXPORT byte
           zsys_mcast_ttl (void);

       //  *** Draft method, for development use, may change without warning ***
       //  Print formatted string. Format is specified by variable names
       //  in Python-like format style
       //
       //  "%(KEY)s=%(VALUE)s", KEY=key, VALUE=value
       //  become
       //  "key=value"
       //
       //  Returns freshly allocated string or NULL in a case of error.
       //  Not enough memory, invalid format specifier, name not in args
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT char *
           zsys_zprintf (const char *format, zhash_t *args);

       //  *** Draft method, for development use, may change without warning ***
       //  Return error string for given format/args combination.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT char *
           zsys_zprintf_error (const char *format, zhash_t *args);

       //  *** Draft method, for development use, may change without warning ***
       //  Print formatted string. Format is specified by variable names
       //  in Python-like format style
       //
       //  "%(KEY)s=%(VALUE)s", KEY=key, VALUE=value
       //  become
       //  "key=value"
       //
       //  Returns freshly allocated string or NULL in a case of error.
       //  Not enough memory, invalid format specifier, name not in args
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT char *
           zsys_zplprintf (const char *format, zconfig_t *args);

       //  *** Draft method, for development use, may change without warning ***
       //  Return error string for given format/args combination.
       //  Caller owns return value and must destroy it when done.
       CZMQ_EXPORT char *
           zsys_zplprintf_error (const char *format, zconfig_t *args);

       #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 ());
           }
           #ifdef CZMQ_BUILD_DRAFT_API
           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);
           #endif // CZMQ_BUILD_DRAFT_API
           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);
           zsys_set_thread_name_prefix (0);
           assert (0 == zsys_thread_name_prefix());
           assert (streq ("0", zsys_thread_name_prefix_str()));
           zsys_thread_affinity_cpu_add (0);
           zsys_thread_affinity_cpu_remove (0);
           zsys_set_zero_copy_recv(0);
           assert (0 == zsys_zero_copy_recv());
           zsys_set_zero_copy_recv(1);
           assert (1 == zsys_zero_copy_recv());

           //  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);

           {
               // zhash based printf
               zhash_t *args = zhash_new ();
               zhash_insert (args, "key", "value");
               zhash_insert (args, "ham", "spam");

               char *str = zsys_zprintf ("plain string", args);
               assert (streq (str, "plain string"));
               zstr_free (&str);

               str = zsys_zprintf ("%%a%%", args);
               assert (streq (str, "%a%"));
               zstr_free (&str);

               str = zsys_zprintf ("VALUE=%(key)s123", args);
               assert (streq (str, "VALUE=value123"));
               zstr_free (&str);

               str = zsys_zprintf ("VALUE=%(key)s123, %(ham)s, %(ham)s, %%(nospam)s!!!", args);
               assert (streq (str, "VALUE=value123, spam, spam, %(nospam)s!!!"));
               zstr_free (&str);

               str = zsys_zprintf ("VALUE=%(nokey)s123, %(ham)s, %(ham)s, %%(nospam)s!!!", args);
               assert (!str);

               str = zsys_zprintf_error ("VALUE=%(nokey)s123, %(ham)s, %(ham)s, %%(nospam)s!!!", args);
               assert (streq (str, "Key 'nokey' not found in hash"));
               zstr_free (&str);

               str = zsys_zprintf ("VALUE=%(key)s/%%S", args);
               assert (streq (str, "VALUE=value/%S"));
               zstr_free (&str);

               zhash_destroy (&args);

               //ZPL based printf
               zconfig_t *root = zconfig_new ("root", NULL);
               zconfig_put (root, "zsp", "");
               zconfig_put (root, "zsp/return_code", "0");

               str = zsys_zplprintf ("return_code=%(zsp/return_code)s", root);
               assert (streq (str, "return_code=0"));
               zstr_free (&str);

               zconfig_destroy (&root);
           }

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