From: Karel Zak <kzak@redhat.com>
Date: Thu, 9 Apr 2026 08:16:30 +0000 (+0200)
Subject: irqtop: add vw_printw() fallback for slang builds
X-Git-Url: http://git.ipfire.org/index.cgi?a=commitdiff_plain;h=e67a2ea47738b76e5cb9ccfe8ce28e18e028d755;p=thirdparty%2Futil-linux.git

irqtop: add vw_printw() fallback for slang builds

The vw_printw() function and OK macro are ncurses-specific and not
available in slang's curses compatibility layer. This causes build
failures when configuring with --with-slang.

Add configure/meson checks for vw_printw() availability and provide
a portable fallback implementation using vsnprintf() and waddstr()
when the function is not available.

Addresses: https://github.com/util-linux/util-linux/issues/4177
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/configure.ac b/configure.ac
index 4c824eb12..93f4f8afe 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1223,6 +1223,10 @@ AS_IF([test "x$have_slang" = xyes || test "x$have_ncursesw" = xyes || test "x$ha
 		     AC_DEFINE(HAVE_RESIZETERM, 1,
 			       [Define if curses library has the resizeterm().])
 	])
+	AC_CHECK_LIB([$CURSES_LIB_NAME], vw_printw, [
+		     AC_DEFINE(HAVE_VW_PRINTW, 1,
+			       [Define if curses library has the vw_printw().])
+	])
 ])
 
 
diff --git a/meson.build b/meson.build
index 88c6bdf5f..19f7f02b0 100644
--- a/meson.build
+++ b/meson.build
@@ -320,6 +320,8 @@ foreach curses_libs : [lib_slang, lib_ncursesw, lib_ncurses]
     conf.set('HAVE_USE_DEFAULT_COLORS', have ? 1 : false)
     have = cc.has_function('resizeterm', dependencies : curses_libs)
     conf.set('HAVE_RESIZETERM', have ? 1 : false)
+    have = cc.has_function('vw_printw', dependencies : curses_libs)
+    conf.set('HAVE_VW_PRINTW', have ? 1 : false)
     break
   endif
 endforeach
diff --git a/sys-utils/irqtop.c b/sys-utils/irqtop.c
index d0b331119..c017053e7 100644
--- a/sys-utils/irqtop.c
+++ b/sys-utils/irqtop.c
@@ -86,6 +86,21 @@ struct irqtop_ctl {
 		softirq;
 };
 
+#ifndef OK
+# define OK 0
+#endif
+
+#ifndef HAVE_VW_PRINTW
+static inline int vw_printw(WINDOW *win, const char *fmt, va_list args)
+{
+	char buf[BUFSIZ];
+
+	if (vsnprintf(buf, sizeof(buf), fmt, args) < 0)
+		return ERR;
+	return waddstr(win, buf);
+}
+#endif
+
 static inline int irqtop_printf(struct irqtop_ctl *ctl, const char *fmt, ...)
 {
 	int ret = 0;