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Merged
merged 6 commits into from
Jan 5, 2020
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Add stdlib_experimental_kinds.f90 and use it #63

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4a52299
Add stdlib_experimental_kinds.f90 and use it
certik Jan 2, 2020
2375321
Update src/stdlib_experimental_kinds.f90
certik Jan 2, 2020
4f8ff60
Update src/stdlib_experimental_kinds.f90
certik Jan 2, 2020
bd3067f
Update Makefiles
certik Jan 3, 2020
220421f
Use it in stdlib_experimental_optval
certik Jan 5, 2020
23e0b79
Switch to iso_fortran_env
certik Jan 5, 2020
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Add stdlib_experimental_kinds.f90 and use it
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@certik
certik committed Jan 5, 2020
commit 4a52299a9e1cf1f1c9c73d229d2eab99a43f4c7d
1 change: 1 addition & 0 deletions src/CMakeLists.txt
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Expand Up @@ -3,6 +3,7 @@ set(SRC
stdlib_experimental_io.f90
stdlib_experimental_error.f90
stdlib_experimental_optval.f90
stdlib_experimental_kinds.f90
)

add_library(fortran_stdlib ${SRC})
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2 changes: 1 addition & 1 deletion src/stdlib_experimental_io.f90
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module stdlib_experimental_io
use iso_fortran_env, only: sp=>real32, dp=>real64, qp=>real128
use stdlib_experimental_kinds, only: sp, dp, qp
use stdlib_experimental_error, only: error_stop
use stdlib_experimental_optval, only: optval
implicit none
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10 changes: 10 additions & 0 deletions src/stdlib_experimental_kinds.f90
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module stdlib_experimental_kinds
! Instead of iso_fortran_env, we use iso_c_binding, to be compatible with C
!use iso_fortran_env, only: sp=>real32, dp=>real64, qp=>real128
!use iso_fortran_env, only: int32, int64, int128
use iso_c_binding, only: sp=>c_float, dp=>c_double, qp=>c_float128
use iso_c_binding, only: int32=>c_int32_t, int64=>c_int64_t, int128=>c_int128_t
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@jvdp1 jvdp1 Jan 2, 2020

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Is int128 supported by all compilers?
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@zbeekman zbeekman Jan 2, 2020

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That's a good question. If C has standardized int128 I would image that it is. But I need to consult the standard for more insight.
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@jvdp1 jvdp1 Jan 2, 2020

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At least I don't find c_int128_t in iso_c_binding or int128iniso_fortran_env`
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@certik certik Jan 2, 2020

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But it compiled. It might be only supported by gfortran?
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@zbeekman zbeekman Jan 2, 2020

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The standard says that it will compile, but be set to a special value when not supported (missing) if my memory is correct. So compilation doesn't guarantee existence of the kind. (I think the special value is 0 or a negative integer.)
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@marshallward marshallward Jan 4, 2020

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It looks like C99 has no guaranteed 128-bit integer (long long is "at least 64 bits" and intN_t is only guaranteed up to 64).

Looking at my own include files (libc 2.30), I don't see anything for 128-bit integers except a few places under an __ILP32__ preprocessor flag, which must have been unset when my platform-specific includes were preprocessed for my system.
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@marshallward marshallward Jan 4, 2020

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Also, I think one does need to be careful with quad precision. On its own, it does not have a clear meaning. There are (at least) three active definitions:

https://gcc.gnu.org/onlinedocs/gcc/Floating-Types.html

For example, on my machine, double and long double both point to _Float64. My libc also defines a _Float64x which as best I can tell corresponds to the x86 float80 format.
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@marshallward marshallward Jan 4, 2020

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BTW I am looking at a copy of the 2018 standard now (Table 18.2 in section 18.3.1), and I don't see any reference to c_int128_t in there? Only up to c_int64_t. Also no reference to c_float128.
implicit none
private
public sp, dp, qp, int32, int64, int128
end module
2 changes: 1 addition & 1 deletion src/tests/io/test_loadtxt.f90
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program test_loadtxt
use iso_fortran_env, only: sp=>real32, dp=>real64
use stdlib_experimental_kinds, only: sp, dp
use stdlib_experimental_io, only: loadtxt
use stdlib_experimental_error, only: error_stop
implicit none
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2 changes: 1 addition & 1 deletion src/tests/io/test_loadtxt_qp.f90
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program test_loadtxt_qp
use iso_fortran_env, only: qp=>real128
use stdlib_experimental_kinds, only: qp
use stdlib_experimental_io, only: loadtxt
implicit none

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2 changes: 1 addition & 1 deletion src/tests/io/test_savetxt.f90
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program test_savetxt
use iso_fortran_env, only: sp=>real32, dp=>real64
use stdlib_experimental_kinds, only: sp, dp
use stdlib_experimental_io, only: loadtxt, savetxt
use stdlib_experimental_error, only: assert
implicit none
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2 changes: 1 addition & 1 deletion src/tests/io/test_savetxt_qp.f90
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program test_savetxt_qp
use iso_fortran_env, only: qp=>real128
use stdlib_experimental_kinds, only: qp
use stdlib_experimental_io, only: loadtxt, savetxt
use stdlib_experimental_error, only: assert
implicit none
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