Support taking the -O tag value from apropos(1) key=value search terms;

feature improvement suggested by kn@.
While here, also make "-O value" work from standard input.
OK kn@

2 files changed, 26 insertions, 9 deletions

diff --git a/main.c b/main.c
index d916864d..a0878099 100644
--- a/main.c
+++ b/main.c
@@ -123,7 +123,7 @@ main(int argc, char *argv[])
 	struct manpage	*res, *resp;
 	const char	*progname, *sec, *thisarg;
 	char		*conf_file, *defpaths, *auxpaths;
-	char		*oarg;
+	char		*oarg, *tagarg;
 	unsigned char	*uc;
 	size_t		 i, sz;
 	int		 prio, best_prio;
@@ -368,6 +368,17 @@ main(int argc, char *argv[])
 #endif
 	}
 
+	/*
+	 * Use the first argument for -O tag in addition to
+	 * using it as a search term for man(1) or apropos(1).
+	 */
+
+	if (conf.output.tag != NULL && *conf.output.tag == '\0') {
+		tagarg = argc > 0 && search.argmode == ARG_EXPR ?
+		    strchr(*argv, '=') : NULL;
+		conf.output.tag = tagarg == NULL ? *argv : tagarg + 1;
+	}
+
 	/* man(1), whatis(1), apropos(1) */
 
 	if (search.argmode != ARG_FILE) {
@@ -480,8 +491,10 @@ main(int argc, char *argv[])
 	curp.mp = mparse_alloc(options, curp.os_e, curp.os_s);
 
 	if (argc < 1) {
-		if (use_pager)
+		if (use_pager) {
 			tag_files = tag_init();
+			tag_files->tagname = conf.output.tag;
+		}
 		thisarg = "<stdin>";
 		mandoc_msg_setinfilename(thisarg);
 		parse(&curp, STDIN_FILENO, thisarg);
@@ -518,11 +531,7 @@ main(int argc, char *argv[])
 			if (use_pager) {
 				use_pager = 0;
 				tag_files = tag_init();
-				if (conf.output.tag != NULL &&
-				    tag_files->tagname == NULL)
-					tag_files->tagname =
-					    *conf.output.tag != '\0' ?
-					    conf.output.tag : *argv;
+				tag_files->tagname = conf.output.tag;
 			}
 
 			mandoc_msg_setinfilename(thisarg);
diff --git a/mandoc.1 b/mandoc.1
index 8c47c1c7..7db089fa 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -307,8 +307,16 @@ If no
 is specified, reuse the first command line argument that is not a
 .Ar section
 number.
-This is useful when it is the name of a manual page,
-in particular the name of a library function.
+If that argument is in
+.Xr apropos 1
+.Ar key Ns = Ns Ar val
+format, only the
+.Ar val
+is used rather than the argument as a whole.
+This is useful for commands like
+.Ql man -akO tag Ic=ulimit
+to search for a keyword and jump right to its definition
+in the matching manual pages.
 .It Cm width Ns = Ns Ar width
 The output width is set to
 .Ar width