Index: src/amiga-library.h
==================================================================
--- src/amiga-library.h
+++ src/amiga-library.h
@@ -80,12 +80,13 @@
 	/* strtod() uses sscanf() internally */
 	int (*_Nonnull vsscanf)(const char *_Nonnull restrict,
 	    const char *_Nonnull restrict, va_list);
 #endif
 	void (*_Nonnull exit)(int);
+	int (*_Nonnull atexit)(void (*_Nonnull)(void));
 	of_sig_t _Nullable (*_Nonnull signal)(int, of_sig_t _Nullable);
 	char *_Nullable (*_Nonnull setlocale)(int, const char *_Nullable);
 	int (*_Nonnull _Unwind_Backtrace)(int (*_Nonnull)(void *_Nonnull,
 	    void *_Null_unspecified), void *_Null_unspecified);
 };
 
 extern bool of_init(unsigned int version, struct of_libc *libc, FILE **sF);

Index: src/amiga-library.m
==================================================================
--- src/amiga-library.m
+++ src/amiga-library.m
@@ -636,10 +636,16 @@
 {
 	libc.exit(status);
 
 	OF_UNREACHABLE
 }
+
+int
+atexit(void (*function)(void))
+{
+	return libc.atexit(function);
+}
 
 of_sig_t
 signal(int sig, of_sig_t func)
 {
 	return libc.signal(sig, func);

Index: src/linklib/linklib.m
==================================================================
--- src/linklib/linklib.m
+++ src/linklib/linklib.m
@@ -328,10 +328,11 @@
 		.vsnprintf = vsnprintf,
 #ifdef OF_AMIGAOS_M68K
 		.vsscanf = vsscanf,
 #endif
 		.exit = exit,
+		.atexit = atexit,
 		.signal = signal,
 		.setlocale = setlocale,
 		._Unwind_Backtrace = _Unwind_Backtrace
 	};