Do not break output lines in .Fn function arguments in SYNOPSIS mode.

Following an idea from Franco Fichtner, but implemented more cleanly.
This reduces groff-mandoc-differences in base by a fantastic 7.5%.

3 files changed, 29 insertions, 3 deletions

diff --git a/regress/usr.bin/mandoc/mdoc/Fo/Makefile b/regress/usr.bin/mandoc/mdoc/Fo/Makefile
index 48facb8351c..88adf0c6490 100644
--- a/regress/usr.bin/mandoc/mdoc/Fo/Makefile
+++ b/regress/usr.bin/mandoc/mdoc/Fo/Makefile
@@ -1,8 +1,8 @@
-# $OpenBSD: Makefile,v 1.6 2012/11/18 00:05:28 schwarze Exp $
+# $OpenBSD: Makefile,v 1.7 2013/12/25 00:39:14 schwarze Exp $
 
-REGRESS_TARGETS = basic section noarg font eos
+REGRESS_TARGETS = basic section break noarg font eos
 
-# groff 1.21 does not handle .nr nS
+# groff does not handle .nr nS
 
 SKIP_GROFF ?= section
 
diff --git a/regress/usr.bin/mandoc/mdoc/Fo/break.in b/regress/usr.bin/mandoc/mdoc/Fo/break.in
new file mode 100644
index 00000000000..2a5d1dcd699
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Fo/break.in
@@ -0,0 +1,11 @@
+.Dd December 25, 2013
+.Dt FO-BREAK 1
+.Os OpenBSD
+.Sh NAME
+.Nm Fo-break
+.Nd line breaks in function blocks
+.Sh SYNOPSIS
+.Ft my_long_return_type *
+.Fn my_long_function "my_long_type first_argument" "my_long_type second_argument"
+.Sh DESCRIPTION
+.Fn my_long_function "my_long_type first_argument" "my_long_type second_argument"
diff --git a/regress/usr.bin/mandoc/mdoc/Fo/break.out_ascii b/regress/usr.bin/mandoc/mdoc/Fo/break.out_ascii
new file mode 100644
index 00000000000..a3379b74989
--- /dev/null
+++ b/regress/usr.bin/mandoc/mdoc/Fo/break.out_ascii
@@ -0,0 +1,15 @@
+FO-BREAK(1)                OpenBSD Reference Manual                FO-BREAK(1)
+
+NNAAMMEE
+     FFoo--bbrreeaakk - line breaks in function blocks
+
+SSYYNNOOPPSSIISS
+     _m_y___l_o_n_g___r_e_t_u_r_n___t_y_p_e _*
+     mmyy__lloonngg__ffuunnccttiioonn(_m_y___l_o_n_g___t_y_p_e _f_i_r_s_t___a_r_g_u_m_e_n_t,
+         _m_y___l_o_n_g___t_y_p_e _s_e_c_o_n_d___a_r_g_u_m_e_n_t);
+
+DDEESSCCRRIIPPTTIIOONN
+     mmyy__lloonngg__ffuunnccttiioonn(_m_y___l_o_n_g___t_y_p_e _f_i_r_s_t___a_r_g_u_m_e_n_t, _m_y___l_o_n_g___t_y_p_e
+     _s_e_c_o_n_d___a_r_g_u_m_e_n_t)
+
+OpenBSD                        December 25, 2013                       OpenBSD