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atexit(3) [mojave man page]

ATEXIT(3)						   BSD Library Functions Manual 						 ATEXIT(3)

NAME
atexit -- register a function to be called on exit SYNOPSIS
#include <stdlib.h> int atexit(void (*function)(void)); int atexit_b(void (^function)(void)); DESCRIPTION
The atexit() function registers the given function to be called at program exit, whether via exit(3) or via return from the program's main(). Functions so registered are called in reverse order; no arguments are passed. If the provided function is located in a library that has been dynamically loaded (e.g. by dlopen()), it will be called when the library is unloaded (due to a call to dlclose()) or at program exit. The atexit_b() function is like atexit() except the callback is a block pointer instead of a function pointer. Note: The Block_copy() function (defined in <Blocks.h>) is used by atexit_b() to make a copy of the block, especially for the case when a stack-based block might go out of scope when the subroutine returns. These functions must not call exit(); if it should be necessary to terminate the process while in such a function, the _exit(2) function should be used. (Alternatively, the function may cause abnormal process termination, for example by calling abort(3).) At least 32 functions can always be registered, and more are allowed as long as sufficient memory can be allocated. RETURN VALUES
The atexit() and atexit_b() functions return the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
[ENOMEM] No memory was available to add the function to the list. The existing list of functions is unmodified. SEE ALSO
exit(3) STANDARDS
The atexit() function conforms to ISO/IEC 9899:1990 (``ISO C90''). BSD
September 6, 2002 BSD

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ATEXIT(3)						   BSD Library Functions Manual 						 ATEXIT(3)

NAME
atexit -- register a function to be called on exit LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <stdlib.h> int atexit(void (*function)(void)); int atexit_b(void (^function)(void)); DESCRIPTION
The atexit() function registers the given function to be called at program exit, whether via exit(3) or via return from the program's main(). Functions so registered are called in reverse order; no arguments are passed. These functions must not call exit(); if it should be necessary to terminate the process while in such a function, the _exit(2) function should be used. (Alternatively, the function may cause abnormal process termination, for example by calling abort(3).) At least 32 functions can always be registered, and more are allowed as long as sufficient memory can be allocated. The atexit_b() function behaves identically to atexit(), except that it takes a block, rather than a function pointer. RETURN VALUES
The atexit() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
[ENOMEM] No memory was available to add the function to the list. The existing list of functions is unmodified. [ENOSYS] The atexit_b() function was called by a program that did not supply a _Block_copy() implementation. SEE ALSO
at_quick_exit(3), exit(3) STANDARDS
The atexit() function conforms to ISO/IEC 9899:1990 (``ISO C90''). BSD
September 6, 2002 BSD
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