Inside of a cell definition, arc instances are declared with the "A" line. All arcs are sorted by the arc name. The syntax is:

A<type> | <name> | <nameTD> | <width> | <flags> | <headNode> | <headPortID> | <headX> | <headY> | <tailNode> | <tailPortID> | <tailX> | <tailY> [ | <variable> ]*
<type> | the type of the arc instance. It has the form: [<technology>:]<arc>. If technology is omitted, the technology of the cell is assumed.
<name> | the name of the arc instance.
<nameTD> | a text descriptor for the name (when displayed).
<width> | the difference between width of the arc instance and standard width of this arc's prototype.
<flags> | flags for the arc instance (see below).
<headNode> | the name of the node at the head of the arc instance.
<headPortID> | the ID of the port on the head node (may be blank if there are no choices).
<headX> | the X coordinate of the head of the arc instance.
<headY> | the Y coordinate of the head of the arc instance.
<tailNode> | the name of the node at the tail of the arc instance.
<tailPortID> | the ID of the port on the tail node (may be blank if there are no choices).
<tailX> | the X coordinate of the tail of the arc instance.
<tailY> | the Y coordinate of the tail of the arc instance.
<variable> | a list of variables on the arc instance (see Section 10-4-1).

The <flags> field consists of any of the following letters, sorted alphabetically, with the numeric part at the end:

"A" if the arc instance is hard-to-select.
"B" if the arc instance has an arrow line on the body (use "X" and "Y" for arrow heads).
"F" if the arc instance is NOT fixed-angle (fixed-angle is more common).
"G" if the arc instance has its head connection negated.
"I" if the arc instance has its head NOT extended.
"J" if the arc instance has its tail NOT extended.
"N" if the arc instance has its tail connection negated.
"R" if the arc instance is rigid.
"S" if the arc instance is slidable.
"X" if the arc instance has an arrow on the head (use "B" for an arrow body).
"Y" if the arc instance has an arrow on the tail (use "B" for an arrow body).
Num Any digits at the end are the angle of the arc (in tenths of a degree).

Examples:

`AMetal-1|net@0||1|S1800|contact@0||10|10|pin@0||20|10`
Places a metal-1 arc (from the technology of the cell). The arc is named "net@0", is 1 wider than standard, slidable, and at a 180 degree angle. The arc runs from (10,10) on node "contact@0", to (20,10) on node "pin@0".

`Aschematic:bus|net@161|||IJ2700|busHat@4|s[1:8]|42|14|conn@15|y|42|25`
Places a bus arc (from schematic) named "net@161", standard width, not end-extended on either end, at 270 degrees angle. The bus runs from (42,14) on node busHat@4 (port "s[1:8]") to (42,25) on node "conn@15" (port "y").