On Dec 14, 2:53 pm, lak <l...@nospam.invalidwrote:
Hello firends.
I want to know what is the variable length in c.
I K&R they stated that atleast 31 character.
But I give 1 lakhs length to a variable, but my compiler doesn't say
any error.
It accepts it.Then what is the maximum length to a variable.?
A more appropriate reference is the C language standard. It says:
5.2.4.1 Translation limits
1 The implementation shall be able to translate and execute at least
one program that contains at least one instance of every one of the
following limits:13)
* 127 nesting levels of blocks
* 63 nesting levels of conditional inclusion
* 12 pointer, array, and function declarators (in any combinations)
modifying an arithmetic, structure, union, or incomplete type in a
declaration
* 63 nesting levels of parenthesized declarators within a full
declarator
* 63 nesting levels of parenthesized expressions within a full
expression
* 63 significant initial characters in an internal identifier or a
macro name (each universal character name or extended source character
is considered a single character)
* 31 significant initial characters in an external identifier (each
universal character name specifying a short identifier of 0000FFFF or
less is considered 6 characters, each universal character name
specifying a short identifier of 00010000 or more is considered 10
characters, and each extended source character is considered the same
number of characters as the corresponding universal character name, if
any)14)
* 4095 external identifiers in one translation unit
* 511 identifiers with block scope declared in one block
* 4095 macro identifiers simultaneously defined in one preprocessing
translation unit
* 127 parameters in one function definition
* 127 arguments in one function call
* 127 parameters in one macro definition
* 127 arguments in one macro invocation
* 4095 characters in a logical source line
* 4095 characters in a character string literal or wide string literal
(after concatenation)
* 65535 bytes in an object (in a hosted environment only)
* 15 nesting levels for #included files
* 1023 case labels for a switch statement (excluding those for any
nested switch statements)
* 1023 members in a single structure or union
* 1023 enumeration constants in a single enumeration
* 63 levels of nested structure or union definitions in a single
struct-declaration-list
So you can have up to 63 *initial* characters in an internal
identifier. That means you might make one 100 characters long, but
only the first 63 would be recognized to differentiate it from other
identifiers.
Some pre-C99 implementations may limit to 31 *initial* characters in
an internal identifier. That means you might make one 100 characters
long, but only the first 31 would be recognized to differentiate it
from other identifiers.
