Defined in header <signal.h> #define SIG_DFL /*implementation defined*/ #define SIG_IGN /*implementation defined*/ The SIG_DFL and SIG_IGN macros expand into integral expressions that are not equal to an address of any function. The macros define signal handling strategies for signal() function. Constant Explanation SIG_DFL default signal handling SIG_IGN signal is ignored Example #include <signal.h> #include <stdio.h> int main(void) {

Defined in header <stdlib.h> int at_quick_exit( void (*func)() ); (since C11) Registers the function pointed to by func to be called on quick program termination (via quick_exit). Calling the function from several threads does not induce a data race. The implementation shall support the registration of at least 32 functions. Parameters func - pointer to a function to be called on normal program termination Return value ​0​ if the registration succeeds, nonzero

Defined in header <signal.h> #define SIGTERM /*implementation defined*/ #define SIGSEGV /*implementation defined*/ #define SIGINT /*implementation defined*/ #define SIGILL /*implementation defined*/ #define SIGABRT /*implementation defined*/ #define SIGFPE /*implementation defined*/ Each of the above macro constants expands to an integer constant expression with distinct values, which represent different signals sent to the program. Constant

Defined in header <stdio.h> (1) ​int scanf( const char *format, ... );​ (until C99) ​int scanf( const char *restrict format, ... );​ (since C99) (2) int fscanf( FILE *stream, const char *format, ... ); (until C99) int fscanf( FILE *restrict stream, const char *restrict format, ... ); (since C99) (3) int sscanf( const char *buffer, const char *format, ... ); (until C99) int sscanf( const char *restrict buff

Usage const type qualifier

Causes the remaining portion of the enclosing for, while or do-while loop body to be skipped. Used when it is otherwise awkward to ignore the remaining portion of the loop using conditional statements. Syntax continue ; Explanation The continue statement causes a jump, as if by goto, to the end of the loop body (it may only appear within the loop body of for, while, and do-while loops). For while loop, it acts as. while (/* ... */) { // ... continue; // acts as goto contin

Defined in header <threads.h> void call_once( once_flag* flag, void (*func)(void) ); (1) (since C11) typedef once_flag /* unspecified */ (2) (since C11) #define ONCE_FLAG_INIT /* unspecified */ (3) (since C11) 1) Calls function func exactly once, even if invoked from several threads. The completion of the function func synchronizes with all previous or subsequent calls to call_once with the same flag variable. 2) Complete object type capable of holding a flag

Defined in header <math.h> float asinf( float arg ); (1) (since C99) double asin( double arg ); (2) long double asinl( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define asin( arg ) (4) (since C99) 1-3) Computes the principal values of the arc sine of arg. 4) Type-generic macro: If the argument has type long double, asinl is called. Otherwise, if the argument has integer type or the type double, asin is called

Usage typedef declaration

Usage volatile type qualifier