C Standard Library header files

 

C

Compiler support

Language

Headers

Type support

Program utilities

Variadic function support

Error handling

Dynamic memory management

Strings library

Algorithms

Numerics

Date and time utilities

Input/output support

Localization support

Concurrency support (C11)

Technical Specifications

Symbol index

 

Standard Library headers

<assert.h> <complex.h> (C99) <ctype.h> <errno.h> <fenv.h> (C99) <float.h> <inttypes.h> (C99)       <iso646.h> (C95)

<limits.h> <locale.h> <math.h> <setjmp.h> <signal.h> <stdalign.h> (C11) <stdarg.h> <stdatomic.h> (C11)

<stdbit.h> (C23) <stdbool.h> (C99) <stdckdint.h> (C23) <stddef.h> <stdint.h> (C99) <stdio.h> <stdlib.h> <stdnoreturn.h> (C11)

<string.h> <tgmath.h> (C99) <threads.h> (C11) <time.h> <uchar.h> (C11) <wchar.h> (C95) <wctype.h> (C95)

 

The interface of C standard library is defined by the following collection of headers.

<assert.h>	Conditionally compiled macro that compares its argument to zero
<complex.h> (since C99)	Complex number arithmetic
<ctype.h>	Functions to determine the type contained in character data
<errno.h>	Macros reporting error conditions
<fenv.h> (since C99)	Floating-point environment
<float.h>	Limits of floating-point types
<inttypes.h> (since C99)	Format conversion of integer types
<iso646.h> (since C95)	Alternative operator spellings
<limits.h>	Ranges of integer types
<locale.h>	Localization utilities
<math.h>	Common mathematics functions
<setjmp.h>	Nonlocal jumps
<signal.h>	Signal handling
<stdalign.h> (since C11)	alignas and alignof convenience macros
<stdarg.h>	Variable arguments
<stdatomic.h> (since C11)	Atomic operations
<stdbit.h> (since C23)	Macros to work with the byte and bit representations of types
<stdbool.h> (since C99)	Macros for boolean type
<stdckdint.h> (since C23)	macros for performing checked integer arithmetic
<stddef.h>	Common macro definitions
<stdint.h> (since C99)	Fixed-width integer types
<stdio.h>	Input/output
<stdlib.h>	General utilities: memory management, program utilities, string conversions, random numbers, algorithms
<stdnoreturn.h> (since C11)	noreturn convenience macro
<string.h>	String handling
<tgmath.h> (since C99)	Type-generic math (macros wrapping math.h and complex.h)
<threads.h> (since C11)	Thread library
<time.h>	Time/date utilities
<uchar.h> (since C11)	UTF-16 and UTF-32 character utilities
<wchar.h> (since C95)	Extended multibyte and wide character utilities
<wctype.h> (since C95)	Functions to determine the type contained in wide character data

References

• C23 standard (ISO/IEC 9899:2024):

• 7.1.2 Standard headers

• C17 standard (ISO/IEC 9899:2018):

• 7.1.2 Standard headers (p: 131-132)

• C11 standard (ISO/IEC 9899:2011):

• 7.1.2 Standard headers (p: 181-182)

• C99 standard (ISO/IEC 9899:1999):

• 7.1.2 Standard headers (p: 165)

• C89/C90 standard (ISO/IEC 9899:1990):

• 4.1.2 Standard headers

See also

C++ documentation for C++ Standard Library header files