This is a list of reserved keywords in C. Since they are used by the language, these keywords are not available for re-definition. autobreakcasecharconstcontinuedefaultdodoubleelseenumextern. floatforgotoifinline (since C99)intlongregisterrestrict (since C99)returnshort. signedsizeofstaticstructswitchtypedefunionunsignedvoidvolatilewhile. _Alignas (since C11)_Alignof (since C11)_Atomic (since C11)_Bool (since C99)_Complex (since C99)_Generic (since C11)_Imaginary (since C99)_Noreturn (si

Usage break statement: as the declaration of the statement

Defined in header <stdlib.h> void* bsearch( const void *key, const void *ptr, size_t count, size_t size, int (*comp)(const void*, const void*) ); (1) void* bsearch_s( const void *key, const void *ptr, rsize_t count, rsize_t size, int (*comp)(const void *, const void *, void *), void *context ); (2) (since C11) 1) Finds an element equal to element pointed to by key in an array pointed to by ptr. The array contains count

Causes the enclosing for, while or do-while loop or switch statement to terminate. Used when it is otherwise awkward to terminate the loop using the condition expression and conditional statements. Syntax break ; Appears only within the statement of a loop body (while, do, for) or within the statement of a switch. Explanation After this statement the control is transferred to the statement or declaration immediately following the enclosing loop or switch, as if by goto. Keyword

Defined in header <wchar.h> wint_t btowc( int c ); (since C95) Widens a single-byte character c (reinterpreted as unsigned char) to its wide character equivalent. Most multibyte character encodings use single-byte codes to represent the characters from the ASCII character set. This function may be used to convert such characters to wchar_t. Parameters c - single-byte character to widen Return value WEOF if c is EOF. wide character representation of c if (unsig

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

This section provides definitions for the specific terminology and the concepts used when describing the C programming language. A C program is a sequence of text files (typically header and source files) that contain declarations. They undergo translation to become an executable program, which is executed when the OS calls its main function (unless it is itself the OS or another freestanding program, in which case the entry point is implementation-defined). Certain words in a C program have sp

The C programming language, as of C99, supports Boolean arithmetic with the built-in type _Bool (see _Bool). When the header <stdbool.h> is included, the Boolean type is also accessible as bool. Standard logical operators &&, ||, ! can be used with the Boolean type in any combination. A program may undefine and perhaps then redefine the macros bool, true and false. Macros Macro name Expands to bool _Bool true integer constant 1 false integer constant 0 __bool_t

Usage automatic duration storage-class specifier with no linkage.

Declares a member with explicit width, in bits. Adjacent bit field members may be packed to share and straddle the individual bytes. A bit field declaration is a struct or union member declaration which uses the following declarator: identifier(optional) : width identifier - the name of the bit field that is being declared. The name is optional: nameless bitfields introduce the specified number of bits of padding width - an integer constant expression with a value greater or