https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110798
Bug ID: 110798
Summary: The reusult of sizeof operator followed with an
'unsigned typedef-ed generic integer' type is alway 4
bytes（except char）
Product: gcc
Version: og12 (devel/omp/gcc-12)
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: 13958014620 at 139 dot com
Target Milestone: ---
Some issues arised when doing some tests.
The reusult of sizeof operator followed with an 'unsigned typedef-ed generic
integer' type is always 4 bytes（except char）.
The following example had run in fedora 37 OS with gcc_12.3.1 and
gcc_13.1.0(compiled myself), both versions of gcc show the same issue.
#include <cassert>
int main(int argc, char ** argv){
int ret=0;
typedef char ch_t;
assert( sizeof(unsigned char) == 1); //right
assert( sizeof(ch_t) == 1 ); //right
assert( sizeof(unsigned ch_t) == 1); //the only one right
typedef signed char sch;
assert( sizeof(unsigned char) == 1); //right
assert( sizeof(sch) == 1 ); //right
assert( sizeof(unsigned sch) == 4); //wrong, which should be 1
typedef short sint;
assert( sizeof(unsigned short) == 2 ); //right
assert( sizeof(sint) == 2 ); //right
assert( sizeof(unsigned sint) == 4); //wrong, which should be 8
typedef long lint;
assert( sizeof(unsigned long) == 8); //right
assert( sizeof(lint) == 8 ); //right
assert( sizeof(unsigned lint) == 4); //wrong, which should be 8
typedef long long llint;
assert( sizeof(unsigned long long) == 8); //right
assert( sizeof(llint) == 8 ); //right
assert( sizeof(unsigned llint) ==4); //wrong, which should be 8
/* The same errors as:
'typedef signed short ssint',
'typedef signed long slint',
'typedef signed long long sllint',
'typedef unsigned short usint',
'typedef unsigned long ulint',
'typedef unsigned long long ullint',
so that seems all sizeof(unsigned <typedef-ed char/short/int/long
type>) == 4,
except typedef char ch_t;
*/
return ret;
}
----------- or a version outputting the result on the terminal --------------
#include <iostream>
#include <cassert>
using namespace std;
int main(int argc, char ** argv){
int ret=0;
typedef char ch_t;
cout << "typedef char ch_t;"<<endl;
assert( sizeof(unsigned char) == 1); //right
cout << "\tsizeof(unsigned char)=" << sizeof(unsigned char) <<endl;
assert( sizeof(ch_t) == 1 ); //right
cout << "\tsizeof(ch_t)=" << sizeof(ch_t) <<endl;
assert( sizeof(unsigned ch_t) == 1); //the only one right
cout << "\tsizeof(unsigned ch_t)=" << sizeof(unsigned ch_t) << " --
the only one right"<<endl;
typedef signed char sch;
cout << endl << "typedef signed char sch;"<<endl;
assert( sizeof(unsigned char) == 1); //right
cout << "\tsizeof(unsigned char)=" << sizeof(unsigned char) <<endl;
assert( sizeof(sch) == 1 ); //right
cout << "\tsizeof(sch)=" << sizeof(sch) <<endl;
assert( sizeof(unsigned sch) == 4); //wrong, which should be 1
cout << "\tsizeof(unsigned sch)=" << sizeof(unsigned sch) << " --
wrong"<<endl;
typedef short sint;
cout << endl << "typedef short sint;" <<endl;
assert( sizeof(unsigned short) == 2 ); //right
cout << "\tsizeof(unsigned short)=" << sizeof(unsigned short int)
<<endl;
assert( sizeof(sint) == 2 ); //right
cout << "\tsizeof(sint)=" << sizeof(sint) <<endl;
assert( sizeof(unsigned sint) == 4); //wrong, which should be 8
cout << "\tsizeof(unsigned sint)=" << sizeof(unsigned sint) << " --
wrong"<<endl;
typedef long lint;
cout << endl << "typedef long lint;" <<endl;
assert( sizeof(unsigned long) == 8); //right
cout << "\tsizeof(unsigned long)=" << sizeof(unsigned long int) <<endl;
assert( sizeof(lint) == 8 ); //right
cout << "\tsizeof(lint)=" << sizeof(lint) <<endl;
assert( sizeof(unsigned lint) == 4); //wrong, which should be 8
cout << "\tsizeof(unsigned lint)=" << sizeof(unsigned lint) << " --
wrong"<<endl;
typedef long long llint;
cout << endl << "typedef long long llint;" <<endl;
assert( sizeof(unsigned long long) == 8); //right
cout << "\tsizeof(unsigned long long)=" << sizeof(unsigned long long
int) <<endl;
assert( sizeof(llint) == 8 ); //right
cout << "\tsizeof(llint)=" << sizeof(llint) <<endl;
assert( sizeof(unsigned llint) ==4); //wrong, which should be 8
cout << "\tsizeof(unsigned llint)=" << sizeof(unsigned llint) << " --
wrong"<<endl;
cout << endl << "The same errors as: \n\
'typedef signed short ssint', \n\
'typedef signed long slint', \n\
'typedef signed long long sllint', \n\
'typedef unsigned short usint', \n\
'typedef unsigned long ulint', \n\
'typedef unsigned long long ullint', \n\
so that seems all sizeof(unsigned <typedef-ed char/short/int/long type>) == 4,
\n\
except typedef char ch_t;" << endl;
return ret;
}
These issues can't reproduce in pure C language with GCC 12 and 13.
