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1. C Language V2

Product Information

Environment Specification

Temporary Waivers

1.1 Scope of the Implementation

Question 1: What is the limit on the number of nesting levels of compound statements, iteration control structures, and selection control structures?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 127 nesting levels of compound statements, iteration control structures, and selection control structures, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 2: What is the limit on the number of nesting levels of conditional inclusions?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 63 nesting levels of conditional inclusions, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 3: What is the limit on the number of pointer, array, and function declarators (in any combination) modifying an arithmetic, a structure, a union, or an incomplete type in a declaration?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 12 pointer, array, and function declarators (in any combination) modifying an arithmetic, a structure, a union, or an incomplete type in a declaration, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C, Section 5.2.4.1, Translation Limits.

Question 4: What is the limit on the number of nesting levels of parenthesized declarators within a full declarator?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 63 nesting levels of parenthesized declarators within a full declarator, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C, Section 5.2.4.1, Translation Limits.

Question 5: What is the limit on the number of nesting levels of parenthesized expressions within a full expression?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 63 nesting levels of parenthesized expressions within a full expression, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 6: What is the number of significant initial characters in an internal identifier or macro name?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 63 significant initial characters in an internal identifier or macro name, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 7: What is the number of significant initial characters in an external identifier?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 31 significant initial characters in an external identifier, implementations should avoid imposing fixed translation limits whenever possible.

XSI-conformant systems support the significance of external identifiers up to a length of at least 31 bytes.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 8: What is the limit on the number of external identifiers in one translation unit?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 4095 external identifiers in one translation unit, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 9: What is the limit on the number of identifiers with block scope declared within one block?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 511 identifiers with block scope declared within one block, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 10: What is the limit on the number of macro identifiers simultaneously defined in one translation unit?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 4095 macro identifiers simultaneously defined in one translation unit, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 11: What is the limit on the number of parameters in one function definition?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 127 parameters in one function definition, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 12: What is the limit on the number of arguments in one function call?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 127 arguments in one function call, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 13: What is the limit on the number of parameters in one macro definition?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 127 parameters in one macro definition, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 14: What is the limit on the number of arguments in one macro invocation?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 127 arguments in one macro invocation, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 15: What is the limit on the number of characters in a logical source line?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 4095 characters in a logical source line, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 16: What is the limit on the number of characters in a character string literal or wide string literal (after concatenation)?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 4095 characters in a character string literal or wide string literal (after concatenation), implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 17: What is the limit on the number of bytes in an object (in a hosted environment only)?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 65535 bytes in an object (in a hosted environment only), implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 18: What is the limit on the number of nesting levels for #included files?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 15 nesting levels for #includeed files, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 19: What is the limit on the number of case labels for a switch statement (excluding those for any nested switch statement)?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 1023 case labels for a switch statement (excluding those for any nested switch statement), implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 20: What is the limit on the number of members in a single structure or union?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 1023 members in a single structure or union, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 21: What is the limit on the number of enumeration constants in a single enumeration?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 1023 enumeration constants in a single enumeration, iteration control structures, and selection control structures, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

Question 22: What is the limit on the number of levels of nested structure or union definitions in a single struct-declaration-list?

Response

Rationale

The ISO C specification states that, while the implementation shall be able to translate and execute at least one program that contains at least one instance of 63 levels of nested structure or union definitions in a single struct-declaration-list, implementations should avoid imposing fixed translation limits whenever possible.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.2.4.1, Translation Limits.

1.2 Technical Requirements

Question 23: What conversion rules are applied when converting an integer type to a floating type which cannot represent the result exactly?

Response

Convert to the nearest higher value.
Convert to the nearest lower value.


IEEE round-to-nearest

Rationale

The ISO C specification states that when a value of integer type is converted to a floating type, if the value being converted is in the range of values which can be represented but cannot be represented exactly, the result is either the nearest higher value or nearest lower value, chosen in an implementation-defined manner.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 6.3.1, Arithmetic Operands.

Question 24: What conversion rules are applied when converting a double to a float or a long double to a double or a float which cannot represent the result exactly?

Response

Convert to the nearest higher value.
Convert to the nearest lower value.
Select this item and enter your response below if the above options do not describe the implementation accurately.

IEEE round-to-nearest

Rationale

The ISO C specification states that when converting a double to a float, or a long double to a double or a float, if the value being converted is in the range of values which can be represented but cannot be represented exactly, the result is either the nearest higher value or nearest lower value, chosen in an implementation-defined manner.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 6.3.1, Arithmetic Operands.

Question 25: When mapping sequences of characters in #include directives to external source file names, does the implementation ignore distinctions of alphabetic case and restrict the mapping to 8 significant characters?

Response

Yes   No

Rationale

The ISO C specification states that the implementation may ignore distinctions of alphabetic case and restrict the mapping to 8 significant characters.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 6.10.2, Source File Inclusion.

Question 26: Does the implementation support imaginary types?

Response

Yes   No

Rationale

The ISO C specification states that implementations are not required to provide imaginary types.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 6.7.2, Type Specifiers.

Question 27: What definitions of the function main(), other than the standard two definitions, does the implementation support, if any?

Response

int main(int argc, char **argv, char **envp); int main(int argc, char **argv, char **envp, char **apple); [The value of apple[0] is the first argument to the execve() system call the parent process used.]

Rationale

The ISO C specification states that implementations may provide the main() function in an implementation-defined manner.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 5.1.2.2.1, Program Startup.

Question 28: What extended signed integer types are supported by the implementation, if any?

Response

List them in order of conversion rank, or state "not applicable" if none are supported.

not applicable

Rationale

The ISO C specification states that implementations may provide extended signed integer types.

Reference

ISO/IEC 9899:1999, Programming Languages - C , Section 6.2.5, Types, Section 6.3.1.1, Boolean Characters and Integers.

2. Appendix

To work around a test suite issue (documented in TSD.X.1428) the tests were executed with the compiler flag -D_FORTIFY_SOURCE=0.

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3. Change History

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