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GL3.2 for AIX: Graphics Library (GL) Technical Reference

## circ Subroutine

### Purpose

Outlines a circle.

### Libraries

Graphics Library

C (libgl.a)

FORTRAN (libfgl.a)

### C Syntax

`void circ(Coord x, Coord y, Coord radius)`
`void circi(Icoord x, Icoord y, Icoord radius)`
`void circs(Scoord x, Scoord y, Scoord radius)`

### FORTRAN Syntax

```SUBROUTINE CIRC(x, y, radius)
```SUBROUTINE CIRCI(x, y, radius)
```SUBROUTINE CIRCS(x, y, radius)
Note: For FORTRAN users, the INTEGER*2 version, the CIRCS subroutine, should not be called with integer constant parameters. For example, 2 is an integer constant; JJ is an integer variable. The XL FORTRAN compiler, invoked by the xlf command, stores all integer constants as long integers (INTEGER*4), not as short integers (INTEGER*2). Invoking the short version of this subroutine with an integer constant will result in unexpected behavior.

### Description

The circ subroutine draws an unfilled circle in the x-y plane (z = 0). The system draws the circle using the current line attributes: color, linestyle, linewidth, repeat factor, and writemask.

To create a circle that does not lie in the x-y plane, draw the circle in the x-y plane, then rotate or translate the circle. Circles rotated outside the 2-D x-y plane appear as ellipses.

All of the routines listed in the syntax are functionally the same. They differ only in the type declarations for the coordinates.

### Parameters

 x Specifies the x coordinate of the center of the circle specified in modeling coordinates. y Specifies the y coordinate of the center of the circle specified in modeling coordinates. radius Specifies the length of the radius of the circle.

### Example

The example C language program boxcirc.c uses the circi subroutine to draw a red circle.

### Implementation Specifics

This subroutine is part of GL in the AIXwindows Environment/6000 Version 1, Release 2 with AIXwindows/3D Feature.

### Files

 /usr/include/gl/gl.h Contains C language constant and variable type definitions for GL. /usr/include/gl/fgl.h Contains FORTRAN constant and variable type definitions for GL.

### Related Information

Drawing a circular arc with the arc subroutine.

Drawing a filled circular arc with the arcf subroutine.

Drawing a filled circle with the circf subroutine.

Drawing a curve with the crv subroutine.

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