Using {fmt} on IBM i (AS/400) 7.3 ILE C++ compiler

[kunichik]

I added the include/fmt folder to my project
when I include fmt/printf.h in the program, the IBM i 7.3 ILE C++ compiler,
which doesn't fully implement C++11,
I get the following errors:

../fmt/core.h(481) : error : at column 021 - The name "typename std::enable_if" is not a type.

../fmt/core.h(196) : error : at column 001 - The name "typename std::add_rvalue_reference" is not a type.

../fmt/core.h(210) : error : at column 015 - The name "typename std::make_unsigned" is not a type.

../fmt/core.h(662) : error : at column 025 - The text "<" is unexpected. "std::conditional" may be undeclared or ambiguous.

../fmt/core.h(665) : error : at column 070 - The name lookup for "long_type" did not find a declaration.

../fmt/core.h(665) : warning : at column 070 - Declarations for non-dependent names are resolved in the template definition.

../fmt/core.h(665) : warning : at column 070 - "long_type" does not depend on a template argument.

../fmt/core.h(670) : error : at column 020 - The name lookup for "ulong_type" did not find a declaration.

../fmt/core.h(670) : warning : at column 020 - "ulong_type" does not depend on a template argument.

../fmt/core.h(874) : error : at column 027 - "std::forward" is not declared.

../fmt/format.h(597) : error : at column 003 - The template argument must be a type, to match the template parameter.

../fmt/format.h(672) : error : at column 048 - The name "typename std::is_void" is not a type.

../fmt/format.h(677) : error : at column 026 - The text "<" is unexpected.

../fmt/format.h(999) : error : at column 010 - "internal::copy_str" is not declared.

../fmt/format.h(1661) : error : at column 019 - The name lookup for "to_unsigned" did not find a declaration.

../fmt/format.h(1661) : warning : at column 019 - "to_unsigned" does not depend on a template argument.

../fmt/format.h(2019) : error : at column 010 - The text "{" is unexpected.

../fmt/format.h(2900) : error : at column 007 - "internal::is_negative" is not declared.

../fmt/format.h(3258) : error : at column 003 - "internal::check_format_string" is not declared.

../fmt/format.h(398) : error : at column 034 - "internal::to_unsigned" is not declared.

../fmt/ostream.h(78) : error : at column 029 - The text "<" is unexpected. "std::make_unsigned" may be undeclared, ambiguous, or may require "typename" qualification.

[vitaut]

{fmt} version 5.x requires a subset of C++11 including std::enable_if. Version 4.1 supports older compilers so you might try that instead.

[kunichik]

I downloaded version 4.x and defined the macro FMT_HEADER_ONLY.
It's all right!
But I get the following errors:
../fmt/format.h(2136) : error : at column 040 - "uintptr_t" is not declared.

Note:
The IBM i (AS/400) has 64 bit integers and 128 bit pointers, so there is no such type in
cstdint or "stdint.h"

Can intptr_t be replaced by another type, e.g. unsigned int ?

I've replaced this type as follows:

void write_pointer(const void *p) {
    spec_.flags_ = HASH_FLAG;
    spec_.type_ = 'x';
    //writer_.write_int(reinterpret_cast<uintptr_t>(p), spec_);
    writer_.write_int(reinterpret_cast<unsigned int>(p), spec_);
}

and my test programm works.

[vitaut]

Can intptr_t be replaced by another type, e.g. unsigned int ?

AFAIK the integral type should be large enough for the cast to be valid. A better option is to have a struct of two 64-bit integers, bitcast the pointer to it and then write those two integers.

[vitaut]

or use non-standard 128-bit integral type if available.

[kunichik]

or use non-standard 128-bit integral type if available.

128-bit integral type isn't available

but i have uint64_t in stdint.h
https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_73/rtref/stdinth.htm

what if i typedef here something like this:

#ifdef __UINTPTR_T_AS400
  typedef uint64_t uintptr_t 
#endif

?

[vitaut]

what if i typedef here something like this

Sure if you are OK with the cast being not particularly kosher.

[kunichik]

Sure if you are OK with the cast being not particularly kosher.

OK, what if you change reinterpret_cast to uintptr_t for the pointer to another cast ?

e.g. inside write_int method you cast T value to UnsignedType.
what if you replace

writer_.write_int(reinterpret_cast<uintptr_t>(p), spec_);

to

typedef typename internal::IntTraits<T>::MainType UnsignedType;
writer_.write_int(reinterpret_cast<UnsignedType>(p), spec_);

?

[vitaut]

This will have the same issue. As I wrote earlier:

A better option is to have a struct of two 64-bit integers, bitcast the pointer to it and then write those two integers.

[vitaut]

bd81771 adds support for platforms without uintptr_t. You still need a compiler with some C++11 support, but a PR to backport this to the 4.x branch of {fmt} would be welcome.