Defined in header <ctype.h> int isxdigit( int ch ); Checks if the given character is a hexadecimal numeric character (0123456789abcdefABCDEF) or is classified as a hexadecimal character. The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF. Parameters ch - character to classify Return value Non-zero value if the character is an hexadecimal numeric character, zero otherwise. Notes isdigit and isxdigit are

Defined in header <math.h> float expf( float arg ); (1) (since C99) double exp( double arg ); (2) long double expl( long double arg ); (3) (since C99) Defined in header <tgmath.h> #define exp( arg ) (4) (since C99) 1-3) Computes the e (Euler's number, 2.7182818) raised to the given power arg. 4) Type-generic macro: If arg has type long double, expl is called. Otherwise, if arg has integer type or the type double, exp is called. Ot

Defined in header <fenv.h> int fesetround( int round ); (1) (since C99) int fegetround(); (2) (since C99) 1) Attempts to establish the floating-point rounding direction equal to the argument argument round, which is expected to be one of the floating point rounding macros. 2) Returns the value of the floating point rounding macro that corresponds to the current rounding direction. Parameters round - rounding direction, one of floating point rounding macros

Defined in header <stdio.h> (1) ​int vprintf( const char *format, va_list vlist );​ (until C99) ​int vprintf( const char *restrict format, va_list vlist );​ (since C99) (2) int vfprintf( FILE *stream, const char *format, va_list vlist ); (until C99) int vfprintf( FILE *restrict stream, const char *restrict format, va_list vlist ); (since C99) (3) int vsprintf( char *buffer, const char *format, va_list vlist ); (until C99) int vsprintf(

Defined in header <wctype.h> int iswupper( wint_t ch ); (since C95) Checks if the given wide character is an uppercase letter, i.e. one of ABCDEFGHIJKLMNOPQRSTUVWXYZ or any uppercase letter specific to the current locale. Parameters ch - wide character Return value Non-zero value if the wide character is an uppercase letter, zero otherwise. Example #include <stdio.h> #include <wchar.h> #include <wctype.h> #include <locale.h> int

Each expression in C (an operator with its arguments, a function call, a constant, a variable name, etc) is characterized by two independent properties: a type and a value category. Every expression belongs to one of three primary categories: lvalues, function designators, and non-lvalue object expressions (rvalues). Lvalue expressions Lvalue expression is any expression with object type other than the type void, which potentially designates an object (the behavior is undefined if an lvalue

Defined in header <string.h> size_t strlen( const char *str ); (1) size_t strnlen_s( const char *str, size_t strsz ); (2) (since C11) 1) Returns the length of the given null-terminated byte string, that is, the number of characters in a character array whose first element is pointed to by str up to and not including the first null character. The behavior is undefined if str is not a pointer to a null-terminated byte string. 2) Same as (1), except that the function

Defined in header <complex.h> float complex cacoshf( float complex z ); (1) (since C99) double complex cacosh( double complex z ); (2) (since C99) long double complex cacoshl( long double complex z ); (3) (since C99) Defined in header <tgmath.h> #define acosh( z ) (4) (since C99) 1-3) Computes complex arc hyperbolic sine of a complex value z with branch cut at values less than 1 along the real axis. 4) Type-generic macro: If z has

Defined in header <stdio.h> int fseek( FILE *stream, long offset, int origin ); Sets the file position indicator for the file stream stream to the value pointed to by offset. If the stream is open in binary mode, the new position is exactly offset bytes measured from the beginning of the file if origin is SEEK_SET, from the current file position if origin is SEEK_CUR, and from the end of the file if origin is SEEK_END. Binary streams are not required to support SEEK_END, in

Defined in header <stdlib.h> int wctomb( char *s, wchar_t wc ); (1) errno_t wctomb_s(int *restrict status, char *restrict s, rsize_t ssz, wchar_t wc); (2) (since C11) 1) Converts a wide character wc to multibyte encoding and stores it (including any shift sequences) in the char array whose first element is pointed to by s. No more than MB_CUR_MAX characters are stored. If wc is the null character, the null byte is written to s, preceded by any shift sequences neces