Watcom C Library Reference : asin, asinh, assert, atan, atan2, atanh
Watcom C Reference/A - B - C 2021. 6. 14. 15:13
WATCOM C Library Reference : asin, asinh, assert, atan, atan2, atanh
asin
Synopsis : #include <math.h>
double asin( double x);
Description : The asin function computes the principal value of the arcsine of x. A domain error occurs for arguments not in the range [-1,1].
Returns : The asin function returns the arcsine in the range [-π/2, π/2). When the argument is the outside the permissible range, the matherr function is called. Unless the default mather function is replaced, it will set the global variable errno to EDOM, and print a "DOMAIN error" diagnostic message using the stderr stream.
See Also : acos, atan, atan2, matherr
Example :
#include <stdio.h>
#include <math.h>
void main( )
{
printf( "%f\n", asin(.5) );
}
produces the following :
0.523599
Classification : ANSI
Systems : All
asinh
Synopsis : #include <math.h>
double asinh( double x);
Description : The asinh function computes the inverse hyperbolic sine of x.
Returns : The asinh function returns the inverse hyperbolic sine value.
See Also : acosh, atanh, sinh, matherr
Example :
#include <stdio.h>
#include <math.h>
void main( )
{
printf( "%f\n", asinh( 0.5) );
}
produces the following :
0.481212
Classification : WATCOM
Systems : All
assert
Synopsis : #include <assert.h>
void assert ( int expression );
Description : The assert macro prints a diagnostic message upon the stderr stream and terminates the program if expression is false (O). The diagnostic message has the form
Assertion failed: expression, file filename, line linenumber
where filename is the name of the source file and linenumber is the line number of the assertion that failed in the source file. Filename and linenumber are the values of the preprocessing macros __FILE__ and __LINE__ espectively. No action is taken if expression is true (non-zero).
The assert macro is typically used during program development to identify program 10g errors. The given expression should be chosen so that it is true when the program is functioning as intended.
After the program has been debugged, the special "no debug" identifier NDEBUG can be used to remove assert calls from the program when it is re-compiled.
If NDEBUG is defined (with any value) with a -d command line option or with a #define directive, the C preprocessor ignores all assert calls in the program source.
Returns : The assert macro does not return a value.
Example :
#include <stdio.h>
#include <assert.h>
void process string( char *string )
{
/* use assert to check argument */
assert ( string != NULL);
assert ( *string != '\0' );
/* rest of code follows here */
}
void main( )
{
process_string( "hello" );
process_string( "" );
}
Classification : ANSI
Systems : MACRO
atan
Synopsis : #include <math.h>
double atan( double x);
Description : The atan function computes the principal value of the arctangent of x.
Returns : The atan function returns the arctangent in the range (-π/2, π/2).
See Also : acos, asin, atan2
Example :
#include <stdio.h>
#include <math.h>
void main( )
{
printf( "%f\n", atan(.5) );
}
produces the following :
0.463648
Classification : ANSI
Systems : All
atan2
Synopsis : #include <math.h>
double atan2 ( double y, double x);
Description : The atan2 function computes the principal value of the arctangent of y/x, using the signs of both arguments to determine the quadrant of the return value. A domain error occurs if arguments are zero.
Returns : The atan2 function returns the arctangent of y/x, in the range (-π, π). When the argumenti outside the permissible range, the matherr function is called. Unless the default mathem function is replaced, it will set the global variable errno to EDOM, and print a "DOMAIN error" diagnostic message using the stderr stream.
See Also : acos, asin, atan, matherr
Example :
#include <stdio.h>
#include <math.h>
void main( )
{
printf( "%f\n", atan2 ( .5, 1. ) );
}
produces the following :
0.463648
Classification : ANSI
Systems : All
atanh
Synopsis : #include <math.h>
double atanh( double x);
Description : The atanh function computes the inverse hyperbolic tangent of x. A domain error occurs if
the value of x is outside the range (-1, 1).
Returns : The atanh function returns the inverse hyperbolic tangent value. When the argument is outside the permissible range, the matherr function is called. Unless the default matherr function is replaced, it will set the global variable errno to EDOM, and print a "DOMAIN error" diagnostic message using the stderr stream.
See Also : acosh, asinh, matherr, tanh
Example :
#include <stdio.h>
#include <math.h>
void main( )
{
printf( "%f\n", atanh ( 0.5) );
}
produces the following :
0.549306
Classification : WATCOM
Systems : All
This manual describes the WATCOM C library for DOS, Windows, and OS/2, It includes the Standard C Library (as defined in the ANSI C Standard).
WATCOM C Language Reference manual describes the ANSI C Programming language and extensions to it which are supported by WATCOM C/C++ (32bit)
