Defined in header <stdlib.h> (1) size_t mbstowcs( wchar_t *dst, const char *src, size_t len) (until C99) size_t mbstowcs( wchar_t *restrict dst, const char *restrict src, size_t len) (since C99) errno_t mbstowcs_s(size_t *restrict retval, wchar_t *restrict dst, rsize_t dstsz, const char *restrict src, rsize_t len); (2) (since C11) 1) Converts a multibyte character string from the array whose first element is pointed to by src

Defined in header <stdatomic.h> #define ATOMIC_VAR_INIT(value) /* unspecified */ (since C11) Expands to an expression that can be used to initialize an atomic variable of the same type as value. The initial value of atomic object of automatic storage duration that is not initialized using this macro is undefined. The default (zero) initialization of static and thread-local variables produces valid value however. If this macro is not used for initialization of an atomic vari

Defined in header <stdio.h> int remove( const char *fname ); Deletes the file identified by character string pointed to by fname. If the file is currently open by this or another process, the behavior of this function is implementation-defined (in particular, POSIX systems unlink the file name although the file system space is not reclaimed until the last running process closes the file; Windows does not allow the file to be deleted). Parameters fname - pointer to a

Specify storage duration and linkage of objects and functions: auto - automatic duration and no linkage register - automatic duration and no linkage; address of this variable cannot be taken static - static duration and internal linkage (unless at block scope) extern - static duration and external linkage (unless already declared internal) _Thread_local - thread storage duration (since C11) Explanation Storage-class specifiers appear in declarations. At most one specifier may

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

Defined in header <math.h> #define HUGE_VALF /*implementation defined*/ (since C99) #define HUGE_VAL /*implementation defined*/ #define HUGE_VALL /*implementation defined*/ (since C99) The HUGE_VALF, HUGE_VAL and HUGE_VALL macros expand to positive floating point constant expressions which compare equal to the values returned by floating-point functions and operators in case of overflow (see math_errhandling). Constant Explanation HUGE_VALF Expands to po

Defined in header <threads.h> int mtx_timedlock( mtx_t *restrict mutex, const struct timespec *restrict time_point ); (since C11) Blocks the current thread until the mutex pointed to by mutex is locked or until the TIME_UTC based time point pointed to by time_point has been reached. The behavior is undefined if the current thread has already locked the mutex and the mutex is not recursive. The behavior is undefined if the mutex does not support timeout. P

Defined in header <stdlib.h> int atoi( const char *str ); long atol( const char *str ); long long atoll( const char *str ); (since C99) Interprets an integer value in a byte string pointed to by str. Discards any whitespace characters until the first non-whitespace character is found, then takes as many characters as possible to form a valid integer number representation and converts them to an integer value. The valid integer value consists of the fo

An object whose identifier is declared without the storage-class specifier _Thread_local, and either with external or internal linkage or with the storage-class specifier static, has static storage duration. Its lifetime is the entire execution of the program and its stored value is initialized only once, prior to program startup. Notes Since its stored value is initialized only once, an object with static storage duration can profile the invocations of a function. The other use of the keywo

Usage declaration of an enumeration type