Move signal handling to processes

So far, libweb installed a signal handler so as to handle SIGTERM,
SIGPIPE and SIGINT signals so that processes would not have to care
about such details.

However, it is not advisable for libraries to install signal handlers,
as signals are handled on a per-process basis. The previous approach
would be incompatible if several instances of the library were allocated
by the same process.

Unfortunately, this has the undesired side effect of adding the
boilerplate code into the process.

1 files changed, 51 insertions, 0 deletions

diff --git a/doc/man3/handler_notify_close.3 b/doc/man3/handler_notify_close.3
new file mode 100644
index 0000000..3cc4130
--- /dev/null
+++ b/doc/man3/handler_notify_close.3
@@ -0,0 +1,51 @@
+.TH HANDLER_NOTIFY_CLOSE 3 2024-07-13 0.4.0 "libweb Library Reference"
+
+.SH NAME
+handler_notify_close \- tell a web server handler object to close gracefully
+
+.SH SYNOPSIS
+.LP
+.nf
+#include <libweb/handler.h>
+.P
+int handler_notify_close(struct handler *\fIh\fP);
+.fi
+
+.SH DESCRIPTION
+The
+.IR handler_notify_close (3)
+function notifies
+.I h
+to exit the loop entered to by
+.IR handler_loop (3).
+.IR h
+must have been returned by a previous call to
+.IR handler_alloc (3).
+
+This function is
+.IR async-signal-safe ,
+so it can be safely called from a signal handler. This is intentional,
+as applications would typically want to close the server on specific
+signals, such as
+.I SIGINT
+or
+.IR SIGTERM .
+
+.SH RETURN VALUE
+On success, zero is returned. On error, a negative integer is returned.
+
+.SH ERRORS
+No errors are defined.
+
+.SH SEE ALSO
+.BR handler_alloc (3),
+.BR handler_loop (3),
+.BR libweb_handler (7).
+
+.SH COPYRIGHT
+Copyright (C) 2023-2024 libweb contributors
+.P
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.