Standard library header <cstdlib>
From cppreference.com
This header was originally in the C standard library as <stdlib.h>.
This header provides miscellaneous utilities. Symbols defined here are used by several library components.
Types | |
| structure type, returned by std::div (typedef) | |
| structure type, returned by std::ldiv (typedef) | |
(C++11) |
structure type, returned by std::lldiv (typedef) |
| unsigned integer type returned by the sizeof operator (typedef) | |
Macro constants | |
| indicates program execution status (macro constant) | |
MB_CUR_MAX |
maximum number of bytes in a multibyte character with the current locale (macro constant) |
| implementation-defined null pointer constant (macro constant) | |
| maximum possible value generated by std::rand (macro constant) | |
Functions | |
Process control | |
| causes abnormal program termination (without cleaning up) (function) | |
| causes normal program termination with cleaning up (function) | |
(C++11) |
causes quick program termination without completely cleaning up (function) |
(C++11) |
causes normal program termination without cleaning up (function) |
| registers a function to be called on std::exit() invocation (function) | |
(C++11) |
registers a function to be called on std::quick_exit invocation (function) |
| calls the host environment's command processor (function) | |
| access to the list of environment variables (function) | |
Memory management | |
| allocates memory (function) | |
(C++17) |
allocates aligned memory (function) |
| allocates and zeroes memory (function) | |
| expands or shrinks previously allocated memory block (function) | |
| deallocates previously allocated memory (function) | |
Numeric string conversion | |
| converts a byte string to a floating point value (function) | |
(C++11) |
converts a byte string to an integer value (function) |
(C++11) |
converts a byte string to an integer value (function) |
(C++11) |
converts a byte string to an unsigned integer value (function) |
| converts a byte string to a floating-point value (function) | |
Wide string manipulation | |
| returns the number of bytes in the next multibyte character (function) | |
| converts the next multibyte character to wide character (function) | |
| converts a wide character to its multibyte representation (function) | |
| converts a narrow multibyte character string to wide string (function) | |
| converts a wide string to narrow multibyte character string (function) | |
Miscellaneous algorithms and math | |
| generates a pseudo-random number (function) | |
| seeds pseudo-random number generator (function) | |
| sorts a range of elements with unspecified type (function) | |
| searches an array for an element of unspecified type (function) | |
(C++11) |
computes absolute value of an integral value (|x|) (function) |
(C++11) |
computes quotient and remainder of integer division (function) |
Synopsis
namespace std {
using size_t = /* see description */; // freestanding
using div_t = /* see description */; // freestanding
using ldiv_t = /* see description */; // freestanding
using lldiv_t = /* see description */; // freestanding
}
#define NULL /* see description */ // freestanding
#define EXIT_FAILURE /* see description */ // freestanding
#define EXIT_SUCCESS /* see description */ // freestanding
#define RAND_MAX /* see description */
#define MB_CUR_MAX /* see description */
namespace std {
// Exposition-only function type aliases
extern "C" using /* c-atexit-handler */ = void(); // exposition only
extern "C++" using /* atexit-handler */ = void(); // exposition only
extern "C" using /* c-compare-pred */ = // exposition only
int(const void*, const void*);
extern "C++" using /* compare-pred */ = // exposition only
int(const void*, const void*);
// start and termination
[[noreturn]] void abort() noexcept; // freestanding
int atexit(/* c-atexit-handler */* func) noexcept; // freestanding
int atexit(/* atexit-handler */* func) noexcept; // freestanding
int at_quick_exit(/* c-atexit-handler */* func) noexcept; // freestanding
int at_quick_exit(/* atexit-handler */* func) noexcept; // freestanding
[[noreturn]] void exit(int status); // freestanding
[[noreturn]] void _Exit(int status) noexcept; // freestanding
[[noreturn]] void quick_exit(int status) noexcept; // freestanding
char* getenv(const char* name);
int system(const char* string);
// C library memory allocation
void* aligned_alloc(size_t alignment, size_t size);
void* calloc(size_t nmemb, size_t size);
void free(void* ptr);
void* malloc(size_t size);
void* realloc(void* ptr, size_t size);
double atof(const char* nptr);
int atoi(const char* nptr);
long int atol(const char* nptr);
long long int atoll(const char* nptr);
double strtod(const char* nptr, char** endptr);
float strtof(const char* nptr, char** endptr);
long double strtold(const char* nptr, char** endptr);
long int strtol(const char* nptr, char** endptr, int base);
long long int strtoll(const char* nptr, char** endptr, int base);
unsigned long int strtoul(const char* nptr, char** endptr, int base);
unsigned long long int strtoull(const char* nptr, char** endptr, int base);
// multibyte / wide string and character conversion functions
int mblen(const char* s, size_t n);
int mbtowc(wchar_t* pwc, const char* s, size_t n);
int wctomb(char* s, wchar_t wchar);
size_t mbstowcs(wchar_t* pwcs, const char* s, size_t n);
size_t wcstombs(char* s, const wchar_t* pwcs, size_t n);
// C standard library algorithms
void* bsearch(const void* key, const void* base, // freestanding
size_t nmemb, size_t size, /* c-compare-pred */* compar);
void* bsearch(const void* key, const void* base, // freestanding
size_t nmemb, size_t size, /* compare-pred */* compar);
void qsort(void* base, size_t nmemb, size_t size, // freestanding
/* c-compare-pred */* compar);
void qsort(void* base, size_t nmemb, size_t size, // freestanding
/* compare-pred */* compar);
// low-quality random number generation
int rand();
void srand(unsigned int seed);
// absolute values
constexpr int abs(int j); // freestanding
constexpr long int abs(long int j); // freestanding
constexpr long long int abs(long long int j); // freestanding
constexpr /* floating-point-type */
abs(/* floating-point-type */ j); // freestanding-deleted
constexpr long int labs(long int j); // freestanding
constexpr long long int llabs(long long int j); // freestanding
constexpr div_t div(int numer, int denom); // freestanding
constexpr ldiv_t div(long int numer, long int denom); // freestanding
constexpr lldiv_t div(long long int numer, long long int denom); // freestanding
constexpr ldiv_t ldiv(long int numer, long int denom); // freestanding
constexpr lldiv_t lldiv(long long int numer, long long int denom); // freestanding
}
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 286 | C++98 | the definition of size_t was not provided in <cstdlib>
|
provided |