exceptions: hack to store errno in string object.

Basic idea: when we throw an exception that pertains to a
system error which has an errno code, we can stick the errno
into the memory area of the character string, into the wchar_t
that immediately follows the null terminator. We can do this
because strings track their actual allocation size.

A pair of setter/getter functions to set and retrieve this
value are provided, and all functions in the code which can
set such a code are updated to do so, simply by calling the
newly added uw_ethrowf that drop-in replaces for uw_throwf.

* lib.[ch] (string_set_code, string_get_code): New functions.

* unwind.[ch] (uw_ethrowf): New function.

* eval.c (eval_init): Register string-set-code and
string-get-code intrinsics.

* ftw.c (ftw_wrap): Switch to uw_ethrowf.

* parser.c (open_txr_file): Likewise.

* socket.c (dgram_overflow): Store the ENOBUFS error in errno,
and use uw_ethrowf instead uw_throwf.
(dgram_get_byte_callback, dgram_flush, sock_bind, to_connect,
open_sockfd, sock_connect, sock_listen, sock_accept,
sock_shutdown, sock_timeout, socketpair_wrap): Switch to
uw_ethrowf.

* stream.c (dev_null_get_fd, stdio_maybe_read_error,
stdio_maybe_error, stdio_close, pipe_close, open_directory,
open_file, open_fileno, open_tail, fds_subst,
open_subprocess, open_command, remove_path, rename_path,
tmpfile_wrap, mkdtemp_wrap, mkstemp_wrap): Switch to uw_ethrowf.

* sysif.c (mkdir_wrap, ensure_dir, chdir_wrap, getcwd_wrap,
rmdir_wrap, mknod_wrap, mkfifo_wrap, chmod_wrap, do_chown,
symlink_wrap, link_wrap, readlink_wrap, close_wrap, val
exec_wrap, stat_impl, do_utimes, pipe_wrap, poll_wrap,
getgroups_wrap, setuid_wrap, seteuid_wrap, setgid_wrap,
setegid_wrap, setgroups_wrap, getresuid_wrap, setresuid_wrap,
setresgid_wrap, crypt_wrap, uname_wrap, opendir_wrap,
getrlimit_wrap, setrlimit_wrap): Likewise.

* termios.c (tcgetattr_wrap, tcsetattr_wrap, tcsendbreak_wrap,
tcdrain_wrap, tcflush_wrap, tcflow_wrap): Likewise.

* tests/018/errno.tl: New file.

* txr.1: Documented.

* stdlib/doc-syms.tl: Updated.

1 files changed, 14 insertions, 12 deletions

diff --git a/stdlib/doc-syms.tl b/stdlib/doc-syms.tl
index 2f95f333..8875254b 100644
--- a/stdlib/doc-syms.tl
+++ b/stdlib/doc-syms.tl
@@ -81,7 +81,7 @@
       ("<!" "N-02B10DF9")
       ("<-" "N-02B10DF9")
       ("<=" "D-001E")
-      ("=" "D-0077")
+      ("=" "D-0078")
       (">" "D-0060")
       (">=" "D-0053")
       ("TXR_COMPAT" "N-03F5D03D")
@@ -296,8 +296,8 @@
       ("cdar" "N-001FA3CB")
       ("cdddddr" "N-001FA3CB")
       ("cddr" "N-001FA3CB")
-      ("cdr" "D-0076")
-      ("ceil" "D-007B")
+      ("cdr" "D-0077")
+      ("ceil" "D-007C")
       ("ceil-rem" "N-02DE978F")
       ("ceil1" "N-02C8FF28")
       ("chain" "N-00C53CF7")
@@ -409,7 +409,7 @@
       ("copy-tree-iter" "N-025C3140")
       ("copy-vec" "N-010E7635")
       ("cos" "D-0021")
-      ("cosh" "D-007F")
+      ("cosh" "D-0080")
       ("count-if" "N-00BBC726")
       ("count-until-match" "N-00EFD668")
       ("countq" "N-01DF131F")
@@ -637,11 +637,11 @@
       ("eprototype" "N-036B1BDB")
       ("eq" "N-02550B35")
       ("eql" "N-02550B35")
-      ("equal" "D-0079")
+      ("equal" "D-007A")
       ("equot" "N-02ACCDDF")
       ("erange" "N-036B1BDB")
       ("erofs" "N-036B1BDB")
-      ("errno" "N-03A7137C")
+      ("errno" "D-0076")
       ("error" "N-015466AD")
       ("espipe" "N-036B1BDB")
       ("esrch" "N-036B1BDB")
@@ -726,7 +726,7 @@
       ("file-put" "N-0041C2E5")
       ("file-put-buf" "N-02AE3A31")
       ("file-put-json" "D-002A")
-      ("file-put-jsons" "D-007C")
+      ("file-put-jsons" "D-007D")
       ("file-put-lines" "N-0041C2E5")
       ("file-put-string" "N-0041C2E5")
       ("fileno" "N-008ACF75")
@@ -739,7 +739,7 @@
       ("filter-equal" "N-03136087")
       ("filter-string-tree" "N-00C9EEB0")
       ("finalize" "N-01230613")
-      ("finally" "D-0078")
+      ("finally" "D-0079")
       ("find" "N-00C9DFF6")
       ("find-frame" "N-02B97226")
       ("find-frames" "N-02B97226")
@@ -1114,7 +1114,7 @@
       ("listp" "N-03F70343")
       ("lnew" "N-0230059D")
       ("lnew*" "N-021E6FDC")
-      ("load" "D-0080")
+      ("load" "D-0081")
       ("load-for" "N-0020A085")
       ("load-time" "D-0047")
       ("loff-t" "N-01153D9E")
@@ -1476,7 +1476,7 @@
       ("push-after-load" "N-01F489FE")
       ("pushhash" "N-022660B2")
       ("pushnew" "N-02C37AB0")
-      ("put-buf" "D-007E")
+      ("put-buf" "D-007F")
       ("put-byte" "D-002F")
       ("put-carray" "N-00737951")
       ("put-char" "D-0003")
@@ -1486,7 +1486,7 @@
       ("put-line" "N-012163C3")
       ("put-lines" "N-0367B282")
       ("put-obj" "N-025DB229")
-      ("put-string" "D-007A")
+      ("put-string" "D-007B")
       ("put-strings" "N-0367B282")
       ("pwd" "N-0047F5F6")
       ("qquote" "N-01665185")
@@ -1572,7 +1572,7 @@
       ("replace-struct" "N-01A8343B")
       ("replace-tree-iter" "N-01225FF3")
       ("replace-vec" "N-01F59E62")
-      ("require" "D-007D")
+      ("require" "D-007E")
       ("reset-struct" "N-002A609F")
       ("rest" "N-02288559")
       ("ret" "N-033F39EF")
@@ -1820,7 +1820,9 @@
       ("string-encode" "N-033502F8")
       ("string-extend" "N-03D5358A")
       ("string-finish" "N-0295275B")
+      ("string-get-code" "N-01CF6D14")
       ("string-lt" "N-03ABBED1")
+      ("string-set-code" "N-01CF6D14")
       ("stringp" "N-00BB392B")
       ("strsignal" "N-00234BED")
       ("struct" "D-001B")