Is ‘long unsigned’ as valid as ‘unsigned long’ in C?

by

The ISO C11 standard states in 6.2.5 Types:

There are five standard signed integer types, designated as signed char, short int, int, long int, and long long int.

For each of the signed integer types, there is a corresponding (but different) unsigned integer type (designated with the keyword unsigned) that uses the same amount of storage (including sign information) and has the same alignment requirements.

However there’s no mandate in that section as to the order in which the base type and unsigned modifier appears.

The controlling section is later in the standard, 6.7.2 Type specifiers, paraphrased here:

Type specifiers are void, char, short, int, long, float, double, signed, unsigned, _Bool, _Complex, <struct-or-union-specifier>, <enum-specifier>, and <typedef-name>.

At least one type specifier shall be given in the declaration specifiers in each declaration, and in the specifier-qualifier list in each struct declaration and type name. Each list of type specifiers shall be one of the following multisets (delimited by commas, when there is more than one multiset per item); the type specifiers may occur in any order, possibly intermixed with the other declaration specifiers.

It then goes on to list all the multisets, such as unsigned long, or unsigned long int.

But the important phrase there is the type specifiers may occur in any order, meaning that all of these are valid for that multiset:

unsigned long
long unsigned

unsigned long int
unsigned int long
long unsigned int
long int unsigned
int unsigned long
int long unsigned

More Related Contents:

  1. How I can correct my c code?
  2. Can I change the datatype of previously declared variable in C?
  3. Is char signed or unsigned by default?
  4. What does a type followed by _t (underscore-t) represent?
  5. What is time_t ultimately a typedef to?
  6. Are all data pointers the same size in one platform for all data types? [duplicate]
  7. Where in memory are my variables stored in C?
  8. Objective-C : BOOL vs bool
  9. Is char guaranteed to be exactly 8-bit long? [duplicate]
  10. How do I check if a variable is of a certain type (compare two types) in C?
  11. Question about C behaviour for unsigned integer underflow
  12. C99 boolean data type?
  13. What is the correct type for array indexes in C?
  14. Any guaranteed minimum sizes for types in C?
  15. Difference between signed / unsigned char [duplicate]
  16. how to check if the input is a number or not in C?
  17. In C, what is the correct syntax for declaring pointers?
  18. Why do we define INT_MIN as -INT_MAX – 1? [duplicate]
  19. Difference between size_t and unsigned int?
  20. Why doesn’t C have unsigned floats?
  21. Is void a data type in C?
  22. min and max value of data type in C
  23. Difference between _Bool and bool types in C?
  24. what is the unsigned datatype?
  25. plain C: opening a directory with fopen()
  26. How to use C library created by MATLAB Coder codegen in C program with emxArray arguments?
  27. Why / when to use `intptr_t` for type-casting in C?
  28. What kind of C11 data type is an array according to the AMD64 ABI
  29. Returning function pointer type
  30. What defines an opaque type in C, and when are they necessary and/or useful?

Leave a Comment