Program support utilities

Program termination

The following functions manage program termination and resources cleanup.

Defined in header <stdlib.h>
abort	causes abnormal program termination (without cleaning up) (function)
exit	causes normal program termination with cleaning up (function)
quick_exit (C11)	causes normal program termination without completely cleaning up (function)
_Exit (C99)	causes normal program termination without cleaning up (function)
atexit	registers a function to be called on exit() invocation (function)
at_quick_exit (C11)	registers a function to be called on quick_exit invocation (function)
EXIT_SUCCESSEXIT_FAILURE	indicates program execution execution status (macro constant)

Unreachable control flow

Defined in header <stddef.h>
unreachable (C23)	marks unreachable point of execution (function macro)

Communicating with the environment

Defined in header <stdlib.h>
system	calls the host environment's command processor (function)
getenvgetenv_s (C11)	access to the list of environment variables (function)

Signals

Several functions and macro constants for signal management are provided.

Defined in header <signal.h>
signal	sets a signal handler for particular signal (function)
raise	runs the signal handler for particular signal (function)
sig_atomic_t	the integer type that can be accessed as an atomic entity from an asynchronous signal handler (typedef)
SIG_DFLSIG_IGN	defines signal handling strategies (macro constant)
SIG_ERR	error was encountered (macro constant)
Signal types
SIGABRTSIGFPESIGILLSIGINTSIGSEGVSIGTERM	defines signal types (macro constant)

Non-local jumps

Defined in header <setjmp.h>
setjmp	saves the context (function macro)
longjmp	jumps to specified location (function)
Types
jmp_buf	execution context type (typedef)

References

• C17 standard (ISO/IEC 9899:2018):
• 7.13 Nonlocal jumps <setjmp.h> (p: 191-192)
• 7.14 Signal handling <signal.h> (p: 193-195)
• 7.22 General utilities <stdlib.h> (p: 248-262)
• 7.31.7 Signal handling <signal.h> (p: 332)
• 7.31.12 General utilities <stdlib.h> (p: 333)
• C11 standard (ISO/IEC 9899:2011):
• 7.13 Nonlocal jumps <setjmp.h> (p: 262-264)
• 7.14 Signal handling <signal.h> (p: 265-267)
• 7.22 General utilities <stdlib.h> (p: 340-360)
• 7.31.7 Signal handling <signal.h> (p: 455)
• 7.31.12 General utilities <stdlib.h> (p: 456)
• C99 standard (ISO/IEC 9899:1999):
• 7.13 Nonlocal jumps <setjmp.h> (p: 243-245)
• 7.14 Signal handling <signal.h> (p: 246-248)
• 7.20 General utilities <stdlib.h> (p: 306-324)
• 7.26.6 Signal handling <signal.h> (p: 401)
• 7.26.10 General utilities <stdlib.h> (p: 402)
• C89/C90 standard (ISO/IEC 9899:1990):
• 4.6 NON-LOCAL JUMPS <setjmp.h>
• 4.7 SIGNAL HANDLING <signal.h>
• 4.10 GENERAL UTILITIES <stdlib.h>
• 4.13.5 Signal handling <signal.h>
• 7.13.7 General utilities <stdlib.h>

See also

C++ documentation for Program support utilities