zsys(3)
=======

NAME
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zsys - system-level methods

SYNOPSIS
--------
----
//  Callback for interrupt signal handler
typedef void (zsys_handler_fn) (int signal_value);

//  Set interrupt handler (NULL means external handler)
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 network interface name to use for broadcasts
//  Use this to force the interface for beacons
//  This is experimental; may be merged into zbeacon class.
CZMQ_EXPORT void
    zsys_set_interface (char *iinterface);

//  Return network interface name to use for broadcasts.
//  Returns "" if no interface was set.
//  This is experimental; may be merged into zbeacon class.
CZMQ_EXPORT char *
    zsys_interface (void);

//  Return 1 if file exists, else zero
CZMQ_EXPORT bool
    zsys_file_exists (const char *filename);

//  Return size of file, or -1 if not found
CZMQ_EXPORT ssize_t
    zsys_file_size (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
CZMQ_EXPORT mode_t
    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 a 
//  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, ...);

//  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);

//  Format a string with variable arguments, returning a freshly allocated
//  buffer. If there was insufficient memory, returns NULL.
CZMQ_EXPORT char *
    zsys_vprintf (const char *format, va_list argptr);

//  Self test of this class
CZMQ_EXPORT int
    zsys_test (bool verbose);
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DESCRIPTION
-----------

The zsys class provides a portable wrapper for miscellaneous functions
that we want to wrap but which don't fit into any of the existing
classes. Eventually all non-portable functionality might be moved here
but for now it covers only file systems.


EXAMPLE
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.From zsys_test method
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    zsys_handler_reset ();
    zsys_handler_set (NULL);
    zsys_handler_set (NULL);
    zsys_handler_reset ();
    zsys_handler_reset ();

    int 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);

    rc = zsys_dir_create ("%s/%s", ".", ".testsys/subdir");
    assert (rc == 0);
    when = zsys_file_modified ("./.testsys/subdir");
    assert (when > 0);
    rc = zsys_dir_delete ("%s/%s", ".", ".testsys/subdir");
    assert (rc == 0);

    char *string = s_vprintf ("%s %02x", "Hello", 16);
    assert (streq (string, "Hello 10"));
    free (string);
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SEE ALSO
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linkczmq:czmq[7]