Defined in header <string.h> size_t strspn( const char *dest, const char *src ); Returns the length of the maximum initial segment (span) of the null-terminated byte string pointed to by dest, that consists of only the characters found in the null-terminated byte string pointed to by src. The behavior is undefined if either dest or src is not a pointer to a null-terminated byte string. Parameters dest - pointer to the null-terminated byte string to be analyzed src

Defined in header <complex.h> float cimagf( float complex z ); (1) (since C99) double cimag( double complex z ); (2) (since C99) long double cimagl( long double complex z ); (3) (since C99) Defined in header <tgmath.h> #define cimag( z ) (4) (since C99) 1-3) Returns the imaginary part of z. 4) Type-generic macro: if z has type long double complex, long double imaginary, or long double, cimagl is called. If z has type float complex

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 <threads.h> void thrd_yield(); (since C11) Provides a hint to the implementation to reschedule the execution of threads, allowing other threads to run. Parameters (none). Return value (none). Notes The exact behavior of this function depends on the implementation, in particular on the mechanics of the OS scheduler in use and the state of the system. For example, a first-in-first-out realtime scheduler (SCHED_FIFO in Linux) would suspend the curren

Defined in header <signal.h> void (*signal( int sig, void (*handler) (int))) (int); Sets the error handler for signal sig. The signal handler can be set so that default handling will occur, signal is ignored, or an user-defined function is called. When signal handler is set to a function and a signal occurs, it is implementation defined whether signal(sig, SIG_DFL) will be executed immediately before the start of signal handler. Also, the implementation can prevent some imp

Defined in header <wchar.h> wint_t getwchar(); (since C95) Reads the next wide character from stdin. Parameters (none). Return value the obtained wide character or WEOF if an error has occurred or the end of file reached. References C11 standard (ISO/IEC 9899:2011): 7.29.3.7 The getwchar function (p: 424) C99 standard (ISO/IEC 9899:1999): 7.24.3.7 The getwchar function (p: 369-370) See also getchar reads a character from stdin (function) fgetwcge

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 declaration of an enumeration type

Usage conditionally-supported type specifier for Fortran language linkage. May be used with function declarations and other external declarations to indicate that the calling convention and name mangling is suitable for linking with translation units written in the Fortran programming language.

Defined in header <stdlib.h> #define EXIT_SUCCESS /*implementation defined*/ #define EXIT_FAILURE /*implementation defined*/ The EXIT_SUCCESS and EXIT_FAILURE macros expand into integral expressions that can be used as arguments to the exit function (and, therefore, as the values to return from the main function), and indicate program execution status. Constant Explanation EXIT_SUCCESS successful execution of a program EXIT_FAILURE unsuccessful execution of