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Compute the arccosine of an angle
#include <math.h>
double acos( double x );
float acosf( float x );
- x
- The cosine for which you want to find the angle.
libm
Use the -l m option to
qcc
to link against this library.
These functions compute the
arccosine (specified in radians) of x.
The arccosine in the range (0, π).
|
If an error occurs, these functions return 0, but this is also a valid
mathematical result.
If you want to check for errors, set
errno
to 0, call the function, and then check errno again.
These functions don't change errno if no errors occurred. |
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
int main( void )
{
printf( "%f\n", acos(.5) );
return EXIT_SUCCESS;
}
produces the output:
1.047197
ANSI,
POSIX 1003.1
Safety: | |
Cancellation point |
No |
Interrupt handler |
No |
Signal handler |
No |
Thread |
Yes |
asin(),
atan(),
atan2()
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