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QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running QNX Neutrino 7.1.
Utilities & Libraries
C Library Reference
S
setdomainname()
Set the domain name of the current host

QNX Momentics IDE User's Guide
This User's Guide describes version 7.1 of the Integrated Development Environment (IDE) that's part of the QNX Momentics tool suite.
QNX Software Development Platform
QNX SDP is a cross-compiling and debugging environment, including an IDE and command-line tools, for building binary images and programs for target boards running QNX Neutrino 7.1.
- Quickstart Guide
- OS Components & Operations
- Audio & Graphics API
- Multimedia
- Networking Middleware
- Programming
- Sensor Framework
- System Security Guide
  The QNX System Security Guide is intended for both system integrators who are responsible for the security of a QNX Neutrino RTOS system and developers who want to create a QNX Neutrino resource manager free from vulnerabilities.
- Utilities & Libraries
  - Addon Interfaces Library Reference
  - C Library Reference
    - What's in a Function Description?
    - Manifests
    - Character Sets
    - A
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      - sandbox_attach()
        Attach a sandbox
      - sandbox_create()
        Create a sandbox.
      - sandbox_delete()
        Delete a sandbox.
      - scalb()
        Load the exponent of a radix-independent floating point number
      - scalbln(), scalblnf(), scalblnl()
        Load the exponent of a radix-independent floating point number
      - scalbn(), scalbnf(), scalbnl()
        Load the exponent of a radix-independent floating point number
      - _scalloc()
        Allocate space for an array
      - scandir()
        Scan a directory
      - scanf()
        Scan formatted input from stdin
      - sched_getparam()
        Get the current scheduling parameters of a process
      - sched_get_priority_adjust()
        Calculate the allowable priority for the scheduling policy
      - sched_get_priority_max()
        Get the maximum priority for the scheduling policy
      - sched_get_priority_min()
        Get the minimum priority for the scheduling policy
      - sched_getscheduler()
        Get the current scheduling policy for a process
      - sched_param
        Structure that describes scheduling parameters
      - sched_rr_get_interval()
        Get the execution time limit of a process
      - sched_setparam()
        Change the priority of a process
      - sched_setscheduler()
        Change the priority and scheduling policy of a process
      - sched_yield()
        Yield to other ready threads at the same priority
      - SchedCtl(), SchedCtl_r()
        Control the scheduler
      - SchedGet(), SchedGet_r()
        Get the scheduling policy and parameters for a thread
      - SchedGetCpuNum()
        Get the index of the CPU that a thread is currently running on
      - SchedInfo(), SchedInfo_r()
        Get scheduler information
      - SchedSet(), SchedSet_r()
        Set the scheduling policy and parameters for a thread
      - SchedYield(), SchedYield_r()
        Yield to other threads
      - searchenv()
        Search the directories listed in an environment variable
      - seed48()
        Initialize the seed for a sequence of pseudo-random numbers
      - seekdir()
        Set the position for the next read of the directory stream
      - select(), pselect()
        Check for files that are ready for reading or writing or have an exceptional condition pending
      - select_attach()
        Attach a file descriptor to a dispatch handle
      - select_detach()
        Detach a file descriptor from a dispatch handle
      - select_query()
        Decode the last select event
      - sem_clockwait()
        Wait on a semaphore with a timeout measured against a specific clock
      - sem_close()
        Close a named semaphore
      - sem_destroy()
        Destroy an unnamed semaphore
      - sem_getvalue()
        Get the value of a named or unnamed semaphore
      - sem_init()
        Initialize an unnamed semaphore
      - sem_open()
        Create or access a named semaphore
      - sem_post()
        Increment a named or unnamed semaphore
      - sem_timedwait(), sem_timedwait_monotonic()
        Wait on a named or unnamed semaphore, with a timeout
      - sem_trywait()
        Wait on a named or unnamed semaphore, but don't block
      - sem_unlink()
        Destroy a named semaphore
      - sem_wait()
        Wait on a named or unnamed semaphore
      - send()
        Send a message to a connected socket
      - sendmmsg()
        Send multiple messages to a socket
      - sendmsg()
        Send a message and its header to a socket
      - sendto()
        Send a message to a socket at a specific address
      - servent
        Structure for information from the services database
      - set_ids_from_arg()
        Change the caller's identifiers, based on a given string
      - set_lowest_fd()
        Specify the lowest acceptable file descriptor
      - setbuf()
        Associate a buffer with a stream
      - setbuffer()
        Assign block buffering to a stream
      - setdomainname()
        Set the domain name of the current host
      - setegid()
        Set the effective group ID for a process
      - setenv()
        Create or change an environment variable
      - seteuid()
        Set the effective user ID
      - setgid()
        Set the real, effective and saved set-group IDs
      - setfsent()
        Open the filesystem table (/etc/fstab) file
      - setgrent()
        Rewind to the start of the group database file
      - setgroups()
        Set supplementary group IDs
      - setgroupspid()
        Set supplementary group IDs for a child process
      - sethostent()
        Open the host database file
      - sethostname()
        Set the name of the current host
      - SETIOV(), SETIOV_CONST()
        Fill in the fields of an iov_t structure
      - setitimer()
        Set the value of an interval timer
      - setjmp()
        Save the calling environment for longjmp()
      - setkey()
        Set the key used in encryption
      - setlinebuf()
        Assign line buffering to a stream
      - setlocale()
        Select a program's locale
      - setlogmask()
        Set the syslogd system log priority mask
      - setnetent()
        Open the network name database file
      - setpgid()
        Join or create a process group
      - setpgrp()
        Set the process group
      - setprotoent()
        Open the protocol name database file
      - setpwent()
        Rewind the password database file
      - setregid()
        Set real and effective group IDs
      - setreuid()
        Set the real and effective user IDs for the calling process
      - setrlimit(), setrlimit64()
        Set the limit on a system resource
      - setservent()
        Open the network services database file
      - setsid()
        Create a new session
      - setsockopt()
        Set options associated with a socket
      - setsockprefix() (io-pkt)
        Set or get the prefix for the networking stack path for the current thread
      - setspent()
        Rewind the shadow password database file
      - setstate()
        Reset the state of a pseudo-random number generator
      - settimeofday()
        Set the time and date
      - setuid()
        Set the real, effective and saved user IDs
      - setutent()
        Return to the beginning of the user-information file
      - setvbuf()
        Associate a buffer with a stream
      - _sfree()
        Deallocate a block of memory
      - shm_create_handle()
        Create a handle so a specific process can access a shared memory object
      - shm_ctl(), shm_ctl_special()
        Give special attributes to a shared memory object
      - shm_delete_handle()
        Delete a handle to a shared memory object
      - shm_open()
        Open a shared memory object based on a pathname
      - shm_open_handle()
        Open a shared memory object based on a handle
      - shm_revoke()
        Revoke mappings to shared memory
      - shm_unlink()
        Remove the name of a shared memory object
      - shutdown()
        Shut down part of a full-duplex connection
      - shutdown_system(), shutdown_system_with_reason()
        Shut down the system
      - sigaction()
        Examine or specify the action associated with a signal
      - struct sigaction
        Structure that specifies how to handle a signal
      - sigaddset()
        Add a signal to a set
      - sigblock()
        Add to the mask of signals to block
      - sigdelset()
        Delete a signal from a set
      - sigemptyset()
        Initialize a set to contain no signals
      - sigevent
        Structure that describes an event
      - sigfillset()
        Initialize a set to contain all signals
      - siginfo_t
        Information about a signal
      - sigismember()
        See if a given signal is in a given set
      - siglongjmp()
        Restore the environment saved by sigsetjmp(), including the signal mask
      - sigmask()
        Construct a mask for a signal number
      - signal()
        Set handling for exceptional conditions
      - SignalAction(), SignalAction_r()
        Examine and/or specify actions for signals
      - SignalKill(), SignalKill_r()
        Send a signal to a process group, process, or thread
      - SignalKillSigval(), SignalKillSigval_r()
        Send a signal to a process group, process, or thread
      - SignalProcmask(), SignalProcmask_r()
        Modify or examine a thread's signal-blocked mask
      - SignalSuspend(), SignalSuspend_r()
        Suspend a thread until a signal is received
      - SignalWaitinfo(), SignalWaitinfo_r()
        Select a pending signal
      - SignalWaitinfoMask(), SignalWaitinfoMask_r()
        Block a set of signals and then select a pending signal
      - signbit()
        Determine whether a floating-point number is negative
      - sigpause()
        Wait for a signal
      - sigpending()
        Examine the set of pending, masked signals for a process
      - sigprocmask()
        Modify or examine a thread's signal-blocked mask
      - sigqueue()
        Queue a signal to a process
      - sigsetjmp()
        Save the environment, including the signal mask
      - sigsetmask()
        Set the mask of signals to block
      - sigsuspend()
        Replace the signal mask, and then suspend the thread
      - sigtimedwait()
        Wait for a signal or a timeout
      - sigunblock()
        Unblock signals
      - sigwait()
        Wait for a pending signal
      - sigwaitinfo()
        Wait for a specified signal and return its information
      - sin(), sinf(), sinl()
        Calculate the sine of an angle
      - sinh(), sinhf(), sinhl()
        Compute the hyperbolic sine
      - sleep()
        Suspend a thread for a given length of time
      - _sleepon_broadcast()
        Wake up multiple threads
      - _sleepon_destroy()
        Destroy a sleepon
      - _sleepon_init()
        Initialize a sleepon
      - _sleepon_lock()
        Lock a sleepon
      - _sleepon_signal()
        Wake up a single thread
      - _sleepon_unlock()
        Unlock a sleepon
      - _sleepon_wait()
        Wait on a sleepon lock
      - slog2_close_log()
        Close a system logger file
      - slog2_dump_logs_to_file()
        Write a snapshot of slog2 logs to a file
      - slog2_find_buffer()
        Find the handle for a buffer with a given name
      - slog2_get_buffer_info()
        Get information about a slogger2 buffer
      - slog2_get_log_info()
        Get information about a log file
      - slog2_get_verbosity()
        Get the verbosity level of the entire buffer set
      - slog2_hash()
        Convert an input string into an obfuscated non-reversible hash string
      - slog2_obfuscate()
        Obfuscate file and directory names by replacing some characters
      - slog2_open_log()
        Open a system log for parsing
      - slog2_packet_cmp()
        Compare two slogger2 packets
      - slog2_packet_info_t
        Structure containing information about a packet
      - slog2_parse_all()
        Parse all slogger2 files
      - slog2_parse_dynamic_buffer(), slog2_parse_static_buffer()
        Parse a slogger2 buffer
      - slog2_register()
        Register and allocate a new slog2 buffer set
      - slog2_reset()
        Reset the state of slogger2 for the process
      - slog2_set_default_buffer()
        Set the default slog2 logging buffer
      - slog2_set_verbosity()
        Set the verbosity level for the entire buffer set
      - slog2c()
        Log a constant string in a slog2 buffer
      - slog2f()
        Log a printf-style string in a slog2 buffer
      - slog2fa()
        Log a printf-style string in a slog2 buffer
      - slogb()
        Send a message to the system logger
      - slogf()
        Send a message to the system logger
      - slogi()
        Send a message to the system logger
      - _smalloc()
        Allocate memory in blocks
      - snprintf()
        Write formatted output to a character array, up to a given maximum number of characters
      - sockatmark()
        Determine whether a socket is at the out-of-band mark
      - socket()
        Create an endpoint for communication
      - socketpair()
        Create a pair of connected sockets
      - sopen()
        Open a file for shared access
      - sopenfd()
        Open for shared access a file associated with a given descriptor
      - spawn()
        Create and execute a new child process
      - spawnl()
        Spawn a child process, given a list of arguments
      - spawnle()
        Spawn a child process, given a list of arguments and an environment
      - spawnlp()
        Spawn a child process, given a list of arguments and a relative path
      - spawnlpe()
        Spawn a child process, given a list of arguments, an environment, and a relative path
      - spawnp()
        Create and execute a new child process, given a relative path
      - spawnv()
        Spawn a child process, given a vector of arguments
      - spawnve()
        Spawn a child process, given a vector of arguments and an environment
      - spawnvp()
        Spawn a child process, given a vector of arguments and a relative path
      - spawnvpe()
        Spawn a child process, given a vector of arguments, an environment, and a relative path
      - sprintf()
        Print formatted output into a string
      - sqrt(), sqrtf(), sqrtl()
        Calculate the nonnegative square root of a number
      - srand()
        Start a new sequence of pseudo-random integers
      - srand48()
        Initialize a sequence of pseudo-random numbers
      - srandom()
        Set the seed for a pseudo-random number generator
      - _srealloc()
        Allocate, reallocate or free a block of memory
      - sscanf()
        Scan input from a character string
      - stat(), stat64()
        Get information about a file or directory, given a path
      - struct stat
        Data structure for information about a file or directory
      - stat_convert_form()
        Convert a stat structure from one form to another
      - static_assert()
        Display a diagnostic message at compile time
      - statvfs(), statvfs64()
        Get filesystem information, given a path
      - stderr
        The standard error stream
      - stdin
        The standard input stream
      - stdout
        The standard output stream
      - stpcpy()
        Copy a string and return a pointer to the end of the result
      - stpncpy()
        Copy a fixed-length string and return a pointer to the end of the result
      - straddstr()
        Concatenate one string on to the end of another
      - strcasecmp()
        Compare two strings, ignoring case
      - strcasestr()
        Find one string inside another, ignoring case
      - strcat()
        Concatenate two strings
      - strchr(), strchr_isr()
        Find the first occurrence of a character in a string
      - strcmp()
        Compare two strings
      - strcoll()
        Compare two strings, using the locale's collating sequence
      - strcpy(), strcpy_isr()
        Copy a string
      - strcspn()
        Count the characters at the beginning of a string that aren't in a given character set
      - strdup()
        Create a duplicate of a string
      - strerror()
        Convert an error number into an error message
      - strerror_r()
        Convert an error number into an error message (reentrant)
      - strftime()
        Format a time into a string
      - strlcat(), strlcpy()
        Size-bounded string copying and concatenation
      - strlen(), strlen_isr()
        Compute the length of a string
      - strlwr()
        Convert a string to lowercase
      - strncasecmp()
        Compare two strings, ignoring case, up to a given length
      - strncat()
        Concatenate two strings, up to a maximum length
      - strncmp()
        Compare two strings, up to a given length
      - strncpy()
        Copy a string, to a maximum length
      - strndup()
        Create a duplicate of a string, up to a maximum length
      - strnlen()
        Compute the length of a string, to a maximum number of bytes
      - strpbrk()
        Find the first character in a string that's in a given character set
      - strptime()
        Convert a string into a time
      - strrchr()
        Find the last occurrence of a character in a string
      - strrev()
        Reverse a string
      - strsep()
        Separate a string into pieces marked by given delimiters
      - strsignal()
        Return the description of a signal
      - strspn()
        Count the characters at the beginning of a string that are in a given character set
      - strstr()
        Find one string inside another
      - strtod(), strtof(), strtold()
        Convert a string into a double-precision number
      - strtoimax(), strtoumax()
        Convert a string into an integer
      - strtok()
        Break a string into tokens
      - strtok_r()
        Break a string into tokens (reentrant)
      - strtol(), strtoll()
        Convert a string into a long integer
      - strtoul(), strtoull()
        Convert a string into an unsigned long integer
      - strupr()
        Convert a string to uppercase
      - strxfrm()
        Transform one string into another, to a given length
      - swab()
        Endian-swap a given number of bytes
      - swprintf()
        Print formatted wide-character output into a string
      - swscanf()
        Scan input from a wide-character string
      - symlink()
        Create a symbolic link to a path
      - symlinkat()
        Create a symbolic link to a path, at a given location
      - sync()
        Synchronize filesystem updates
      - SyncCondvarSignal(), SyncCondvarSignal_r()
        Wake up any threads that are blocked on a synchronization object
      - SyncCondvarWait(), SyncCondvarWait_r()
        Block a thread on a synchronization object
      - SyncCtl(), SyncCtl_r()
        Perform an operation on a synchronization object
      - SyncDestroy(), SyncDestroy_r()
        Destroy a synchronization object
      - SyncMutexEvent(), SyncMutexEvent_r()
        Attach an event to a mutex
      - SyncMutexLock(), SyncMutexLock_r()
        Lock a mutex synchronization object
      - SyncMutexRevive(), SyncMutexRevive_r()
        Revive a mutex that's in the DEAD state
      - SyncMutexUnlock(), SyncMutexUnlock_r()
        Unlock a mutex synchronization object
      - SyncSemPost(), SyncSemPost_r()
        Increment a semaphore
      - SyncSemWait(), SyncSemWait_r()
        Wait on a semaphore
      - SyncTypeCreate(), SyncTypeCreate_r()
        Create a synchronization object
      - sysconf()
        Return the value of a configurable system limit or option
      - sysctl(), sysctlbyname()
        Get or set information about the socket manager
      - syslog()
        Write a message to the syslogd system log
      - sysmgr_reboot()
        Reboot the system
      - sysmgr_runstate(), sysmgr_runstate_dynamic()
        Change the runstate of a processor
      - sysmgr_runstate_burst()
        Ask the system to turn on dynamically offlined CPUs
      - SYSPAGE_CPU_ENTRY()
        Return a CPU-specific entry from the system page
      - SYSPAGE_ENTRY()
        Return an entry from the system page
      - _syspage_ptr
        A pointer to the system page
      - SysSrandom()
        Supply entropy to the kernel's pseudorandom number generator
      - system()
        Execute a system command
    - T
    - U
    - V
    - W
    - X
    - Y
    - Z
    - Full Safety Information
    - Glossary
  - Devctl and Ioctl Commands
  - JSON Library Reference
  - PAM Reference
  - Utilities Reference
  - WPA Control Interface Reference
    This document provides a reference for the Wi-Fi Protected Access (WPA) control interface, which provides a C API for the WPA/IEEE 802.11i protocols in Wi-Fi client stations. Application developers who want to control WPA operations and get associated status and event data should read this reference.
QNX Hypervisor
The QNX Hypervisor allows you to run multiple OSs on a target system so you can separate critical and non-critical functions, support a wide variety of applications, and reduce hardware costs.
QNX Software in the Cloud
QNX Software in the Cloud enables developers to use the QNX software in Amazon Web Services (AWS) and Microsoft Azure (Azure).
QNX Advanced Virtualization Frameworks User's Guide
This User's Guide is aimed at all systems integrators and developers who want to design and build embedded systems using the QNX Advanced Virtualization Frameworks.
Typographical Conventions, Support, and Licensing
This section describes the typographical conventions used throughout the documentation and explains how to obtain technical support.

setdomainname()

Set the domain name of the current host

Synopsis:

#include <unistd.h>

int setdomainname( const char * name,
                   size_t namelen );

Arguments:

name: The domain name.
namelen: The length of the name.

Library:

libsocket

Use the -l socket option to qcc to link against this library.

Description:

The setdomainname() function sets the domain name of the host machine. Only the superuser (root) can use this function and even then, the function is normally used only when bootstrapping a system.

Returns:

0: Success.
-1: Failure; errno is set.

Errors:

EFAULT: The name or namelen parameters gave an invalid address.
EPERM: The caller tried to set the domain name without being the superuser.

Classification:

Unix


Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes

Page updated: March 12, 2026