Texas Instruments TMS320C2x User Manual page 183

atan
atan
Syntax
Defined in
Description
Example
atan2
Syntax
Defined in
Description
Example
atexit
Syntax
Defined in
Description
7-24
Polar Arc Tangent
#include <math.h>
double atan(double x );
atan.c in rts.src
The atan function returns the arc tangent of a floating-point argument x. The
return value is an angle in the range [−
double realval, radians;
realval = 1.0;
radians = atan(realval);
Cartesian Arc Tangent
#include <math.h>
double atan2(double y, double x );
atan.c in rts.src
The atan2 function returns the arc tangent of y/x. The function uses the signs
of the arguments to determine the quadrant of the return value. Both argu-
ments cannot be 0. The return value is an angle in the range [−
atan2 (1.0, 1.0)
atan2 (1.0, −1.0)
atan2 (−1.0, 1.0)
atan2 (−1.0, −1.0)
Register Function Callec by Exit()
#include <stdlib.h>
void atexit(void (*fun )(void ));
exit.c in rts.src
The atexit function registers the function that is pointed to by fun, to be called
without arguments at normal program termination. Up to 32 functions can be
registered.
When the program exits through a call to the exit function, a call to abort, or
a return from the main function, the functions that were registered are called
without arguments in reverse order of their registration.
π π
/2, /2] radians.
/* return value = 0 */
π
/4 */
/* returns
π
/4 */
/* returns 3
−π
/4 */
/* returns
π
/* returns −3 /4 */
π π
, ] radians.