From 0197d1dc1c43b808bfbe641ef702b10128fbdc9d Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Sat, 27 Jun 2020 10:55:10 -0700
Subject: New function strsignal.

* configure: detect strsignal, producing HAVE_STRSIGNAL symbol
in config.h.

* sysif.c (strsignal_wrap): New function.
(sysif_init): Register strsignal intrinsic.

* txr.1: Documented.
---
 configure | 19 +++++++++++++++++++
 sysif.c   | 17 +++++++++++++++++
 txr.1     | 10 ++++++++++
 3 files changed, 46 insertions(+)

diff --git a/configure b/configure
index 7ea5bea0..c2c599f5 100755
--- a/configure
+++ b/configure
@@ -2397,6 +2397,25 @@ else
   printf "no\n"
 fi
 
+printf "Checking for strsignal ... "
+
+cat > conftest.c <<!
+#include <string.h>
+#include <signal.h>
+
+int main(void)
+{
+  const char *s = strsignal(SIGABRT);
+  return 0;
+}
+!
+if conftest ; then
+  printf "yes\n"
+  printf "#define HAVE_STRSIGNAL 1\n" >> config.h
+else
+  printf "no\n"
+fi
+
 printf "Checking for setitimer/getitimer ... "
 
 cat > conftest.c <<!
diff --git a/sysif.c b/sysif.c
index e54d6c5f..7d383162 100644
--- a/sysif.c
+++ b/sysif.c
@@ -161,6 +161,20 @@ static val strerror_wrap(val errnum)
   return errno_to_str(eno);
 }
 
+#if HAVE_STRSIGNAL
+
+static val strsignal_wrap(val signum)
+{
+  val self = lit("strsignal");
+  int sig = c_int(signum, self);
+  const char *str = strsignal(sig);
+  return if3(str,
+             string_utf8(strsignal(sig)),
+             format(nil, lit("Unknown signal %s"), signum, nao));
+}
+
+#endif
+
 #if HAVE_DAEMON
 static val daemon_wrap(val nochdir, val noclose)
 {
@@ -2350,6 +2364,9 @@ void sysif_init(void)
 
   reg_fun(intern(lit("errno"), user_package), func_n1o(errno_wrap, 0));
   reg_fun(intern(lit("strerror"), user_package), func_n1o(strerror_wrap, 0));
+#if HAVE_STRSIGNAL
+  reg_fun(intern(lit("strsignal"), user_package), func_n1(strsignal_wrap));
+#endif
   reg_fun(intern(lit("exit"), user_package), func_n1o(exit_wrap, 0));
   reg_fun(intern(lit("at-exit-call"), user_package), func_n1(at_exit_call));
   reg_fun(intern(lit("at-exit-do-not-call"), user_package), func_n1(at_exit_do_not_call));
diff --git a/txr.1 b/txr.1
index 597c0723..84b1dab7 100644
--- a/txr.1
+++ b/txr.1
@@ -60916,6 +60916,16 @@ The return value is
 if the function succeeds, otherwise
 .codn nil .
 
+.coNP Function @ strsignal
+.synb
+.mets (strsignal << signal )
+.syne
+.desc
+The
+.code strsignal
+function returns a character string describing the specified signal number.
+It is based on the same-named POSIX C library function.
+
 .SS* Unix Processes
 
 .coNP Functions @ fork and @ wait
-- 
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