HP OpenVMS SystemsC Programming Language 
Compaq C

Previous  Contents  Index 
Use of the macro invokes a function whose generic parameters have the corresponding real type determined as follows:
For each unsuffixed function in <math.h> for which there is a function in <complex.h> with the same name except for a c prefix, the corresponding typegeneric macro (for both functions) has the same name as the function in <math.h> . The corresponding typegeneric macro for fabs and cabs is fabs . These functions are:
<math.h> <complex.h> typegeneric function function macro    acos cacos acos asin casin asin atan catan atan acosh cacosh acosh asinh casinh asinh atanh catanh atanh cos ccos cos sin csin sin tan ctan tan cosh ccosh cosh sinh csinh sinh tanh ctanh tanh exp cexp exp log clog log pow cpow pow sqrt csqrt sqrt fabs cabs fabs 
If at least one argument for a generic parameter is complex, then use of the macro invokes a complex function; otherwise, use of the macro invokes a real function.
For each unsuffixed function in <math.h> without a cprefixed counterpart in <complex.h> , the corresponding typegeneric macro has the same name as the function. These typegeneric macros are:
atan2 fma llround remainder cbrt fmax log10 remquo ceil fmin log1p rint copysign fmod log2 round erf frexp logb scalbn erfc hypot lrint scalbln exp2 ilogb lround tgamma expm1 ldexp nearbyint trunc fdim lgamma nextafter floor llrint nexttoward 
If all arguments for generic parameters are real, then use of the macro invokes a real function; otherwise, use of the macro results in undefined behavior.
For each unsuffixed function in <complex.h> that is not a cprefixed counterpart to a function in <math.h> , the corresponding typegeneric macro has the same name as the function:
carg conj creal cimag cproj 
Use of the macro with any real or complex argument invokes a complex function.
Consider the following declarations:
#include <tgmath.h> int n; float f; double d; long double ld; float complex fc; double complex dc; long double complex ldc; 
Given these declarations, functions invoked by use of typegeneric macros are as follows:
macro use invokes   exp(n) exp(n), the function acosh(f) acoshf(f) sin(d) sin(d), the function atan(ld) atanl(ld) log(fc) clogf(fc) sqrt(dc) csqrt(dc) pow(ldc, f) cpowl(ldc, f) remainder(n, n) remainder(n, n), the function nextafter(d, f) nextafter(d, f), the function nexttoward(f, ld) nexttowardf(f, ld) copysign(n, ld) copysignl(n, ld) ceil(fc) undefined behavior rint(dc) undefined behavior fmax(ldc, ld) undefined behavior carg(n) carg(n), the function cproj(f) cprojf(f) creal(d) creal(d), the function cimag(ld) cimagl(ld) cabs(fc) cabsf(fc) carg(dc) carg(dc), the function cproj(ldc) cprojl(ldc) 
Typegeneric macros that accept complex arguments also accept imaginary arguments. If an argument is imaginary, the macro expands to an expression whose type is real, imaginary, or complex, as appropriate for the particular function: if the argument is imaginary, then the types of cos , cosh , fabs , carg , cimag , and creal are real; the types of sin , tan , sinh , tanh , asin , atan , asinh , and atanh are imaginary; and the types of the others are complex.
Given an imaginary argument, each of the typegeneric macros cos , sin , tan , cosh , sinh , tanh , asin , atan , asinh , atanh is specified by a formula in terms of real functions:
cos(iy) = cosh(y) sin(iy) = i sinh(y) tan(iy) = i tanh(y) cosh(iy) = cos(y) sinh(iy) = i sin(y) tanh(iy) = i tan(y) asin(iy) = i asinh(y) atan(iy) = i atanh(y) asinh(iy) = i asin(y) atanh(iy) = i atan(y) 
The <time.h> header file defines two macros, and declares four types and several functions for manipulating time and date information. Some functions process local time, which may differ from calendar time because of time zone.
An unsigned integral type of the result of the sizeof operator.
clock_t time_t 
Arithmetic types capable of representing times.
Holds the components of a calendar time, called the brokendown time. The structure contains the following members:
int tm_sec; /* seconds after the minute  [0,61] */ int tm_min; /* minutes after the hour  [0,59] */ int tm_hour; /* hours since midnight  [0,23] */ int tm_mday; /* day of the month  [1,31] */ int tm_mon; /* months since January  [0,11] */ int tm_year; /* years since 1900 */ int tm_wday; /* days since Sunday  [0,6] */ int tm_yday; /* days since January 1  [0,365] */ int tm_isdst; /* Daylight Saving Time flag  0 if */ /* DST not in effect; positive if it is; */ /* negative if information is not available. */
Expands to an implementationdefined null pointer constant.
The number per second of the value returned by the clock function.
char *asctime(const struct tm *timeptr);
Converts a brokendown time in the structure pointed to by timeptr into a 26character string in the form of this example:
Sat Sep 08 08:10:32 1990\n\0
A pointer to the string is returned.
char *ctime(const time_t *timer);
Converts the calendar time pointed to by timer to local time in a string of the form generated by the asctime function. A pointer to the string is returned. The ctime function is equivalent to the following:
asctime(localtime(timer))
struct tm *gmtime(const time_t *timer);
Converts the calendar time pointed to by timer into a brokendown time expressed as Coordinated Universal Time (UTC). The gmtime function returns a pointer to the brokendown time, or a null pointer if UTC is not available.
struct tm *localtime(const time_t *timer);
Converts the calendar time pointed to by timer into a brokendown time expressed as local time. The localtime function returns a pointer to the brokendown time.
size_t strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr);
Places characters into the array pointed to by s as controlled by the string pointed to by format. The format string consists of zero or more conversion specifiers and ordinary multibyte characters. All ordinary multibyte characters (including the terminating null character) are copied unchanged into the array. Each conversion specifier is replaced by the appropriate characters as shown in Table 92. The appropriate characters are determined by the LC_TIME category of the current locale and by the values contained in the structure pointed to by timeptr.
If the total number of resulting characters including the terminating null character is not more than maxsize , the strftime function returns the number of characters placed into the array pointed to by s, not including the terminating null character. Otherwise, 0 is returned, and the array contents are indeterminate.
Determines the processor time used. The clock function returns the processor time used by the program since the beginning of an event related to the program invocation. To determine the time in seconds, divide the return value by the value of the CLOCKS_PER_SEC macro. If the processor time is not available or cannot be represented, the value returned is (clock_t)1 . (To measure the time spent in a program, call the clock function at the start of the program and subtract the return value from that of subsequent calls.)
double difftime(time_t time1, time_t time0);
Returns the difference between the two calendar times time1 and time0, expressed in seconds, as a double .
time_t mktime(struct tm*timeptr);
Converts the brokendown time, expressed as local time, in the structure pointed to by timeptr into a calendar time value with the same encoding as that of the values returned by the time function (that is, a value of type time_t ), which it returns. If the calendar time cannot be represented, the value (time_t)1 is returned.
The original values of the tm_wday and tm_yday time components are ignored, and the original values of the other components are not restricted to the ranges indicated in the previous discussion of struct_tm . Upon successful completion of the function, the values of the tm_wday and tm_yday components are set appropriately, and the other components are set to represent the specified calendar time, but with their values forced to the ranges indicated in the discussion of struct_tm . The final value of tm_wday is not set until tm_mon and tm_year are determined.
Returns the current calendar time. If the calendar time is not available, the value (time_t)1 is returned.
Previous  Next  Contents  Index 