Defined in header <stdio.h> int fflush( FILE *stream ); For output streams (and for update streams on which the last operation was output), writes any unwritten data from the stream's buffer to the associated output device. For input streams (and for update streams on which the last operation was input), the behavior is undefined. If stream is a null pointer, all open output streams are flushed, including the ones manipulated within library packages or otherwise not directl

Executes a statement repeatedly, until the value of expression becomes equal to zero. The test takes place before each iteration. Syntax while ( expression ) statement expression - any expression of scalar type. This expression is evaluated before each iteration, and if it compares equal to zero, the loop is exited. statement - any statement, typically a compound statement, which serves as the body of the loop Explanation A while statement causes the statement (also

A function is a C language construct that associates a compound statement (the function body) with an identifier (the function name). Every C program begins execution from the main function, which either terminates, or invokes other, user-defined or library functions. // function definition. // defines a function with the name "sum" and with the body "{ return x+y; }" int sum(int x, int y) { return x + y; } Functions may accept zero or more parameters, which are initialized from the argume

Defined in header <threads.h> void *tss_get( tss_t tss_key ); (since C11) Returns the value held in thread-specific storage for the current thread identified by tss_key. Different threads may get different values identified by the same key. On thread startup (see thrd_create), the values associated with all TSS keys are NULL. Different value may be placed in the thread-specific storage with tss_set. Parameters tss_key - thread-specific storage key, obtained from tss

Defined in header <complex.h> float complex conjf( float complex z ); (1) (since C99) double complex conj( double complex z ); (2) (since C99) long double complex conjl( long double complex z ); (3) (since C99) Defined in header <tgmath.h> #define conj( z ) (4) (since C99) 1-3) Computes the complex conjugate of z by reversing the sign of the imaginary part. 4) Type-generic macro: if z has type long double complex, long double imag

Usage int type: as the declaration of the type

Defined in header <math.h> #define isnormal(arg) /* implementation defined */ (since C99) Determines if the given floating point number arg is normal, i.e. is neither zero, subnormal, infinite, nor 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 - floating point value

Defined in header <wctype.h> wint_t towctrans( wint_t wc, wctrans_t desc ); (since C95) Maps the wide character wc using the current C locale's LC_CTYPE mapping category identified by desc. Parameters wc - the wide character to map desc - the LC_CTYPE mapping, obtained from a call to wctrans Return value The mapped value of wc using the mapping identified by desc in LC_CTYPE facet of the current C locale. Example #include <locale.h> #include &

Defined in header <math.h> #define isgreater(x, y) /* implementation defined */ (since C99) Determines if the floating point number x is greater than the floating-point number (y), without setting floating-point exceptions. Parameters x - floating point value y - floating point value Return value Nonzero integral value if x > y, ​0​ otherwise. Notes The built-in operator> for floating-point numbers may set FE_INVALID if one or both of the argume

Defined in header <stdlib.h> void quick_exit( int exit_code ); (since C11) Causes normal program termination to occur without completely cleaning the resources. Functions passed to at_quick_exit are called in reverse order of their registration. After calling the registered functions, calls _Exit(exit_code). Parameters exit_code - exit status of the program Return value (none). Example #include <stdlib.h> #include <stdio.h> void f1() { p