2 files changed, 48 insertions, 2 deletions
diff --git a/roff.7 b/roff.7
index dcb81ce5..5456bdc8 100644
--- a/roff.7
+++ b/roff.7
@@ -1715,6 +1715,14 @@ prefixed by an optional sign
 .Sq +
 or
 .Sq - .
+Each number may be followed by one optional scaling unit described below
+.Sx Scaling Widths .
+The following equations hold:
+.Bd -literal -offset indent
+1i = 6v = 6P = 10m = 10n = 72p = 1000M = 240u = 240
+254c = 100i = 24000u = 24000 
+1f = 65536u = 65536
+.Ed
 .Pp
 The following binary operators are implemented.
 Unless otherwise stated, they behave as in the C language:
diff --git a/roff.c b/roff.c
index 435b0bfc..a17d168f 100644
--- a/roff.c
+++ b/roff.c
@@ -1641,8 +1641,46 @@ roff_getnum(const char *v, int *pos, int *res)
 	if (n)
 		*res = -*res;
 
-	*pos = p;
-	return 1;
+	/* Each number may be followed by one optional scaling unit. */
+
+	switch (v[p]) {
+	case 'f':
+		*res *= 65536;
+		break;
+	case 'i':
+		*res *= 240;
+		break;
+	case 'c':
+		*res *= 240;
+		*res /= 2.54;
+		break;
+	case 'v':
+		/* FALLTROUGH */
+	case 'P':
+		*res *= 40;
+		break;
+	case 'm':
+		/* FALLTROUGH */
+	case 'n':
+		*res *= 24;
+		break;
+	case 'p':
+		*res *= 10;
+		*res /= 3;
+		break;
+	case 'u':
+		break;
+	case 'M':
+		*res *= 6;
+		*res /= 25;
+		break;
+	default:
+		p--;
+		break;
+	}
+
+	*pos = p + 1;
+	return(1);
 }
 
 /*