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 |
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structure type, returned by
std::div
(typedef) |
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structure type, returned by
std::ldiv
(typedef) |
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(C++11)
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structure type, returned by
std::lldiv
(typedef) |
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unsigned integer type returned by the
sizeof
operator
(typedef) |
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Macro constants |
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indicates program execution status
(macro constant) |
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MB_CUR_MAX
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maximum number of bytes in a multibyte character with the current locale
(macro constant) |
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implementation-defined null pointer constant
(macro constant) |
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maximum possible value generated by
std::rand
(macro constant) |
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Functions |
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Process control |
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causes abnormal program termination (without cleaning up)
(function) |
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causes normal program termination with cleaning up
(function) |
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(C++11)
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causes quick program termination without completely cleaning up
(function) |
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(C++11)
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causes normal program termination without cleaning up
(function) |
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registers a function to be called on
std::exit()
invocation
(function) |
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(C++11)
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registers a function to be called on
std::quick_exit
invocation
(function) |
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calls the host environment's command processor
(function) |
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access to the list of environment variables
(function) |
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Memory management |
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allocates memory
(function) |
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(C++17)
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allocates aligned memory
(function) |
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allocates and zeroes memory
(function) |
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expands or shrinks previously allocated memory block
(function) |
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deallocates previously allocated memory
(function) |
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Numeric string conversion |
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converts a byte string to a floating point value
(function) |
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(C++11)
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converts a byte string to an integer value
(function) |
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(C++11)
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converts a byte string to an integer value
(function) |
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(C++11)
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converts a byte string to an unsigned integer value
(function) |
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converts a byte string to a floating-point value
(function) |
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Wide string manipulation |
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returns the number of bytes in the next multibyte character
(function) |
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converts the next multibyte character to wide character
(function) |
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converts a wide character to its multibyte representation
(function) |
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converts a narrow multibyte character string to wide string
(function) |
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converts a wide string to narrow multibyte character string
(function) |
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Miscellaneous algorithms and math |
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generates a pseudo-random number
(function) |
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seeds pseudo-random number generator
(function) |
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sorts a range of elements with unspecified type
(function) |
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searches an array for an element of unspecified type
(function) |
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(C++11)
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computes absolute value of an integral value (
|x|
)
(function) |
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(C++11)
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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 |