Defined in header <time.h> struct tm; Structure holding a calendar date and time broken down into its components. Member objects int tm_sec seconds after the minute – [0, 61](until C99) / [0, 60] (since C99)[note 1] 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,

Defined in header <threads.h> int thrd_join( thrd_t thr, int *res ); (since C11) Blocks the current thread until the thread identified by thr finishes execution. If res is not a null pointer, the result code of the thread is put to the location pointed to by res. The termination of the thread synchronizes-with the completion of this function. The behavior is undefined if the thread was previously detached or joined by another thread. Parameters thr - identifier of t

Array is a type consisting of a contiguously allocated nonempty sequence of objects with a particular element type. The number of those objects (the array size) never changes during the array lifetime. Syntax In the declaration grammar of an array declaration, the type-specifier sequence designates the element type (which must be a complete object type), and the declarator has the form: [ static(optional) qualifiers(optional) expression(optional) ] (1) [ qualifiers(optional) static(op

Defined in header <<fenv.h>> #define FE_DFL_ENV /*implementation defined*/ (since C99) The macro constant FE_DFL_ENV expands to an expression of type const fenv_t*, which points to a full copy of the default floating-point environment, that is, the environment as loaded at program startup. Additional macros that begin with FE_ followed by uppercase letters, and have the type const fenv_t*, may be supported by an implementation. Example #include <stdio.h> #

Defined in header <math.h> #define isfinite(arg) /* implementation defined */ (since C99) Determines if the given floating point number arg has finite value i.e. it is normal, subnormal or zero, but not infinite or NaN. The macro returns an integral value. FLT_EVAL_METHOD is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that. Parameters arg - floa

Defined in header <math.h> #define signbit(arg) /* implementation defined */ (since C99) Determines if the given floating point number arg is negative. The macro returns an integral value. Parameters arg - floating point value Return value Nonzero integral value if arg is negative, ​0​ otherwise. Notes This macro detects the sign bit of zeroes, infinities, and NaNs. Along with copysign, this macro is one of the only two portable ways to examine the sign of

The header <tgmath.h> includes the headers <math.h> and <complex.h> and defines several type-generic macros that determine which real or, when applicable, complex function to call based on the types of the arguments. For each macro, the parameters whose corresponding real type in the unsuffixed math.h function is double are known as generic parameters (for example, both parameters of pow are generic parameters, but only the first parameter of scalbn is a generic parameter). Wh

Defined in header <stdio.h> int puts( const char *str ); Writes character string str and a newline to stdout. Parameters str - character string to be written Return value non-negative number on success or EOF otherwise. Example puts() with error checking. #include <stdio.h> #include <stdlib.h> int main(void) { int ret_code = puts("Hello World"); if ((ret_code == EOF) && (ferror(stdout))) /* test whether EOF was reached */

Defined in header <signal.h> int raise( int sig ); Sends signal sig to the program. The signal handler, specified using signal(), is invoked. If the user-defined signal handling strategy is not set using signal() yet, it is implementation-defined whether the signal will be ignored or default handler will be invoked. Parameters sig - the signal to be sent. It can be an implementation-defined value or one of the following values: SIGABRTSIGFPESIGILLSIGINTSIGSEGVSIGT

Defined in header <<fenv.h>> int fetestexcept( int excepts ); (since C99) Determines which of the specified subset of the floating point exceptions are currently set. The argument excepts is a bitwise OR of the floating point exception macros. Parameters excepts - bitmask listing the exception flags to test Return value Bitwise OR of the floating-point exception macros that are both included in excepts and correspond to floating-point exceptions currentl