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Top Forums Programming How to get the sizeof char pointer Post 302322322 by fpmurphy on Wednesday 3rd of June 2009 10:49:09 AM
Old 06-03-2009
Quote:
which is terminated by a null byte by convention.
To clarify, from ISO C99 Sect 7.1.1, a string is a "contiguous sequence of characters terminated by and including the first null character".

Quote:
your two calls to sizeof will always return 4 (size of a pointer).
This is only true if you are on a platform whose programming model is such that a pointer is 32 bits. One such common programming model is ILP32 (Microsoft Windows, 32-bit Linux) where the size of an integer, long and pointer are all 32 bits. Another common programming model is LP64 (64-bit Linux) where the size of an integer is 32 bits but the size of a long and a pointer is 64 bits.
 

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STDINT(7)					       BSD Miscellaneous Information Manual						 STDINT(7)

NAME
stdint -- standard integer types SYNOPSIS
#include <stdint.h> DESCRIPTION
The <stdint.h> header provides source-portable integer types of a specific size, smallest memory footprint with a minimum size, fastest access speed with a minimum size, largest integer size, and those capable of storing pointers. The types int8_t, int16_t, int32_t, and int64_t provide a signed integer type of width 8, 16, 32, or 64 bits, respectively. The types uint8_t, uint16_t, uint32_t, and uint64_t provide an unsigned integer type of width 8, 16, 32, or 64 bits, respectively. These integer types should be used when a specific size is required. The types int_fast8_t, int_fast16_t, int_fast32_t, and int_fast64_t provide the fastest signed integer type with a width of at least 8, 16, 32, or 64 bits, respectively. The types uint_fast8_t, uint_fast16_t, uint_fast32_t, and uint_fast64_t provide the fastest unsigned integer type with a width of at least 8, 16, 32, or 64 bits, respectively. These types should be used when access speed is paramount, and when a specific size is not required. The types int_least8_t, int_least16_t, int_least32_t, and int_least64_t provide the smallest memory footprint signed integer type with a width of at least 8, 16, 32, or 64 bits, respectively. The types uint_least8_t, uint_least16_t, uint_least32_t, and uint_least64_t provide the smallest memory footprint unsigned integer type with a width of at least 8, 16, 32, or 64 bits, respectively. These types should be used when memory storage is of concern, and when a specific size is not required. The type intmax_t provides a signed integer type large enough to hold any other signed integer. The type uintmax_t provides an unsigned integer type large enough to hold any other unsigned integer. These types are generally the largest signed and unsigned integer types avail- able on a specific architecture. The type intptr_t provides a signed integer type with the ability to hold a pointer to void, that can later be converted back to a pointer to void. The type uintptr_t provides an unsigned integer type with the ability to hold a pointer to void, that can later be converted back to a pointer to void. Additionally, the <stdint.h> header defines some macros, but none of them are documented here. STANDARDS
The <stdint.h> header conforms to ISO/IEC 9899:1999 (``ISO C99'') and IEEE Std 1003.1-2001 (``POSIX.1''). HISTORY
The <stdint.h> header was first introduced in FreeBSD 5.0. BSD
September 15, 2002 BSD
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