ref: 698837e7150af19ff6a3f0bf2144dffc81202a55
dir: /sys/man/2/exits/
.TH EXITS 2 .SH NAME exits, _exits, atexit, atexitdont, terminate \- terminate process, process cleanup .SH SYNOPSIS .B #include <u.h> .br .B #include <libc.h> .PP .nf .B void _exits(char *msg) .B void exits(char *msg) .PP .B int atexit(void(*)(void)) .B void atexitdont(void(*)(void)) .fi .SH DESCRIPTION .I Exits is the conventional way to terminate a process. .I _Exits is the underlying system call. They can never return. .PP .I Msg conventionally includes a brief (maximum length .BR ERRLEN ) explanation of the reason for exiting, or a null pointer or empty string to indicate normal termination. The string is passed to the parent process, prefixed by the name and process id of the exiting process, when the parent does a .IR wait (2). .PP Before calling .I _exits with .I msg as an argument, .I exits calls in reverse order all the functions recorded by .IR atexit . .PP .I Atexit records .I fn as a function to be called by .IR exits . It returns zero if it failed, nonzero otherwise. A typical use is to register a cleanup routine for an I/O package. To simplify programs that fork or share memory, .I exits only calls those .IR atexit -registered functions that were registered by the same process as that calling .IR exits . .PP Calling .I atexit twice (or more) with the same function argument causes .I exits to invoke the function twice (or more). .PP There is a limit to the number of exit functions that will be recorded; .I atexit returns 0 if that limit has been reached. .PP .I Atexitdont cancels a previous registration of an exit function. .SH SOURCE .B /sys/src/libc/port/exits.c .br .B /sys/src/libc/port/atexit.c .SH "SEE ALSO" .IR fork (2), .IR wait (2)