Re: [racket-users] Redirecting shared lib stdout
Ah, you're right. I'm still acclimated to BC here. Disregard!
On 5/14/21 7:30 AM, Paulo Matos wrote:
>
> Sage Gerard writes:
>
>> I ran into this issue with rsound. I'm not sure how standard output can
>> be directly captured from a lower-level language in a Racket context
>> when that language can freely ignore the Racket printer and write
>> directly to STDOUT within the same operating system process.
>>
>> I'd hate to just add a "me too", but the only way quick way I could
>> think to handle that was to add another subprocess. If I were wanting to
>> solve the problem in one process, I'd probably extend Racket at the C
>> level and integrate my output with ports.
>>
>> https://docs.racket-lang.org/inside/Ports_and_the_Filesystem.html?q=c%20api
> I was thinking about this until I saw Jon's suggestion - specific to
> binaryen bindings.
>
> However, why would you use the C API (which seems to be mostly focused
> on BC)? My approach would be to wrap the function in C, redirect stdout
> using dup2 to a file and bind that wrapper in racket, read from the file
> and send to `current-output-port`.
>
> Kind regards,
>
> Paulo Matos
>
>> On 5/12/21 3:48 AM, Paulo Matos wrote:
>>> Hi,
>>>
>>> I have a shared library for which I am creating some bindings:
>>> https://github.com/pmatos/racket-binaryen
>>>
>>> There's a function BinaryenModulePrint that prints a WebAssembly module
>>> to stdout.
>>>
>>> When I wrap it in racket, if I do something like:
>>> (define mod ...)
>>> (with-output-to-string (lambda () (BinaryenModulePrint mod)))
>>>
>>> The return value will be "" and it will still print the module to
>>> stdout. I understand! However, I don't know how to solve it in Racket.
>>>
>>> In C, things seem easier because I have access to dup2 and pipe in case
>>> I need to redirect things, however in Racket all my attempts have
>>> failed.
>>>
>>> I have created the simple example:
>>> ```hello.c
>>> #include
>>>
>>> void hello(void) {
>>> printf("hello world!\n");
>>> }
>>> ```
>>>
>>> Compile with `gcc -shared -o hello.so hello.c`.
>>>
>>> Then:
>>> ```hello.rkt
>>> #lang racket/base
>>>
>>> (require racket/port
>>>ffi/unsafe
>>>ffi/unsafe/define)
>>>
>>> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>>> (define-ffi-definer define-hello libhello)
>>> (define-hello hello (_fun -> _void))
>>> (with-output-to-string hello)
>>> ```
>>>
>>> Here's the issue! In C, I can do something like:
>>> ```hello-fix.c
>>> #include
>>> #include
>>> #include
>>> #include
>>>
>>> extern void hello(void);
>>>
>>> int main(void) {
>>> int filefd = open("test.txt", O_WRONLY|O_CREAT, 0666);
>>> dup2(filefd, fileno(stdout));
>>> hello();
>>>
>>> return 0;
>>> }
>>> ```
>>> Compile with `gcc -o hello hello.c hello-fix.c`
>>>
>>> This will, send the output of hello() to a file. Now, in racket
>>> preferably I want to connect what is sent to raw stdout, fd 1, to
>>> current-output-port.
>>>
>>> My thought was that I could create a dup2 ffi binding, and use
>>> unsafe-port->file-descriptor to install the racket pipe file descriptor
>>> in stdout using the dup2 ffi binding but it doesn't work.
>>>
>>> And it doesn't work because the unsafe-port->file-descriptor returns #f,
>>> even though port-waiting-peer? return #f as well (which sort of hints
>>> that maybe the documentation of unsafe-port->file-descriptor is
>>> incomplete.
>>>
>>> The start of my attempt would look like this:
>>>
>>> ```hello.rkt
>>> #lang racket/base
>>>
>>> (require racket/port
>>>ffi/unsafe
>>>ffi/unsafe/define
>>>ffi/unsafe/port)
>>>
>>> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>>>
>>> (define-ffi-definer define-libc (ffi-lib #f))
>>> (define-ffi-definer define-hello libhello)
>>>
>>> (define-libc dup2 (_fun _int _int -> _int))
>>> (define-hello hello (_fun -> _void))
>>>
>>> (define-values (in out) (make-pipe))
>>>
>>> ;; FAILS because (unsafe-port-> ...) return #f
>>> (dup2 (unsafe-port->file-descriptor out) 1)
>>>
>>> ;;...
>>> ;; connect the other end of the port to current-output-port
>>> ;; and use a thread to copy-port
>>> ```
>>>
>>> Surely there must be a better way than this and I would be surprised if
>>> there isn't already something out there in a library but I haven't found
>>> anything yet. Any help here would be great.
>>>
>>> Thanks,
>>>
>>> --
>>> Paulo Matos
>>>
>>> --
>>> You received this message because you are subscribed to the Google Groups
>>> "Racket Users" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an
>>> email to racket-users+unsubscr...@googlegroups.com.
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>>> https://groups.google.com/d/msgid/racket-users/87r1icxuhi.fsf%40linki.tools.
>> --
>> ~slg
>
> --
> Paulo Matos
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Re: [racket-users] Redirecting shared lib stdout
Sage Gerard writes:
> I ran into this issue with rsound. I'm not sure how standard output can
> be directly captured from a lower-level language in a Racket context
> when that language can freely ignore the Racket printer and write
> directly to STDOUT within the same operating system process.
>
> I'd hate to just add a "me too", but the only way quick way I could
> think to handle that was to add another subprocess. If I were wanting to
> solve the problem in one process, I'd probably extend Racket at the C
> level and integrate my output with ports.
>
> https://docs.racket-lang.org/inside/Ports_and_the_Filesystem.html?q=c%20api
I was thinking about this until I saw Jon's suggestion - specific to
binaryen bindings.
However, why would you use the C API (which seems to be mostly focused
on BC)? My approach would be to wrap the function in C, redirect stdout
using dup2 to a file and bind that wrapper in racket, read from the file
and send to `current-output-port`.
Kind regards,
Paulo Matos
>
> On 5/12/21 3:48 AM, Paulo Matos wrote:
>> Hi,
>>
>> I have a shared library for which I am creating some bindings:
>> https://github.com/pmatos/racket-binaryen
>>
>> There's a function BinaryenModulePrint that prints a WebAssembly module
>> to stdout.
>>
>> When I wrap it in racket, if I do something like:
>> (define mod ...)
>> (with-output-to-string (lambda () (BinaryenModulePrint mod)))
>>
>> The return value will be "" and it will still print the module to
>> stdout. I understand! However, I don't know how to solve it in Racket.
>>
>> In C, things seem easier because I have access to dup2 and pipe in case
>> I need to redirect things, however in Racket all my attempts have
>> failed.
>>
>> I have created the simple example:
>> ```hello.c
>> #include
>>
>> void hello(void) {
>>printf("hello world!\n");
>> }
>> ```
>>
>> Compile with `gcc -shared -o hello.so hello.c`.
>>
>> Then:
>> ```hello.rkt
>> #lang racket/base
>>
>> (require racket/port
>> ffi/unsafe
>> ffi/unsafe/define)
>>
>> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>> (define-ffi-definer define-hello libhello)
>> (define-hello hello (_fun -> _void))
>> (with-output-to-string hello)
>> ```
>>
>> Here's the issue! In C, I can do something like:
>> ```hello-fix.c
>> #include
>> #include
>> #include
>> #include
>>
>> extern void hello(void);
>>
>> int main(void) {
>>int filefd = open("test.txt", O_WRONLY|O_CREAT, 0666);
>>dup2(filefd, fileno(stdout));
>>hello();
>>
>>return 0;
>> }
>> ```
>> Compile with `gcc -o hello hello.c hello-fix.c`
>>
>> This will, send the output of hello() to a file. Now, in racket
>> preferably I want to connect what is sent to raw stdout, fd 1, to
>> current-output-port.
>>
>> My thought was that I could create a dup2 ffi binding, and use
>> unsafe-port->file-descriptor to install the racket pipe file descriptor
>> in stdout using the dup2 ffi binding but it doesn't work.
>>
>> And it doesn't work because the unsafe-port->file-descriptor returns #f,
>> even though port-waiting-peer? return #f as well (which sort of hints
>> that maybe the documentation of unsafe-port->file-descriptor is
>> incomplete.
>>
>> The start of my attempt would look like this:
>>
>> ```hello.rkt
>> #lang racket/base
>>
>> (require racket/port
>> ffi/unsafe
>> ffi/unsafe/define
>> ffi/unsafe/port)
>>
>> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>>
>> (define-ffi-definer define-libc (ffi-lib #f))
>> (define-ffi-definer define-hello libhello)
>>
>> (define-libc dup2 (_fun _int _int -> _int))
>> (define-hello hello (_fun -> _void))
>>
>> (define-values (in out) (make-pipe))
>>
>> ;; FAILS because (unsafe-port-> ...) return #f
>> (dup2 (unsafe-port->file-descriptor out) 1)
>>
>> ;;...
>> ;; connect the other end of the port to current-output-port
>> ;; and use a thread to copy-port
>> ```
>>
>> Surely there must be a better way than this and I would be surprised if
>> there isn't already something out there in a library but I haven't found
>> anything yet. Any help here would be great.
>>
>> Thanks,
>>
>> --
>> Paulo Matos
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "Racket Users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to racket-users+unsubscr...@googlegroups.com.
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/racket-users/87r1icxuhi.fsf%40linki.tools.
>
> --
> ~slg
--
Paulo Matos
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Re: [racket-users] Redirecting shared lib stdout
Jon Zeppieri writes:
> Can you use BinaryenModuleWriteText instead? It looks like it was
> added to address your use case. -J
Good point and nice catch.
Although it doesn't solve the issue with racket it does provide a way
out for me to create a safe binding for this function that works within
Racket.
Thanks,
Paulo Matos
>
> On Wed, May 12, 2021 at 3:49 AM Paulo Matos wrote:
>>
>> Hi,
>>
>> I have a shared library for which I am creating some bindings:
>> https://github.com/pmatos/racket-binaryen
>>
>> There's a function BinaryenModulePrint that prints a WebAssembly module
>> to stdout.
>>
>> When I wrap it in racket, if I do something like:
>> (define mod ...)
>> (with-output-to-string (lambda () (BinaryenModulePrint mod)))
>>
>> The return value will be "" and it will still print the module to
>> stdout. I understand! However, I don't know how to solve it in Racket.
>>
>> In C, things seem easier because I have access to dup2 and pipe in case
>> I need to redirect things, however in Racket all my attempts have
>> failed.
>>
>> I have created the simple example:
>> ```hello.c
>> #include
>>
>> void hello(void) {
>> printf("hello world!\n");
>> }
>> ```
>>
>> Compile with `gcc -shared -o hello.so hello.c`.
>>
>> Then:
>> ```hello.rkt
>> #lang racket/base
>>
>> (require racket/port
>> ffi/unsafe
>> ffi/unsafe/define)
>>
>> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>> (define-ffi-definer define-hello libhello)
>> (define-hello hello (_fun -> _void))
>> (with-output-to-string hello)
>> ```
>>
>> Here's the issue! In C, I can do something like:
>> ```hello-fix.c
>> #include
>> #include
>> #include
>> #include
>>
>> extern void hello(void);
>>
>> int main(void) {
>> int filefd = open("test.txt", O_WRONLY|O_CREAT, 0666);
>> dup2(filefd, fileno(stdout));
>> hello();
>>
>> return 0;
>> }
>> ```
>> Compile with `gcc -o hello hello.c hello-fix.c`
>>
>> This will, send the output of hello() to a file. Now, in racket
>> preferably I want to connect what is sent to raw stdout, fd 1, to
>> current-output-port.
>>
>> My thought was that I could create a dup2 ffi binding, and use
>> unsafe-port->file-descriptor to install the racket pipe file descriptor
>> in stdout using the dup2 ffi binding but it doesn't work.
>>
>> And it doesn't work because the unsafe-port->file-descriptor returns #f,
>> even though port-waiting-peer? return #f as well (which sort of hints
>> that maybe the documentation of unsafe-port->file-descriptor is
>> incomplete.
>>
>> The start of my attempt would look like this:
>>
>> ```hello.rkt
>> #lang racket/base
>>
>> (require racket/port
>> ffi/unsafe
>> ffi/unsafe/define
>> ffi/unsafe/port)
>>
>> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>>
>> (define-ffi-definer define-libc (ffi-lib #f))
>> (define-ffi-definer define-hello libhello)
>>
>> (define-libc dup2 (_fun _int _int -> _int))
>> (define-hello hello (_fun -> _void))
>>
>> (define-values (in out) (make-pipe))
>>
>> ;; FAILS because (unsafe-port-> ...) return #f
>> (dup2 (unsafe-port->file-descriptor out) 1)
>>
>> ;;...
>> ;; connect the other end of the port to current-output-port
>> ;; and use a thread to copy-port
>> ```
>>
>> Surely there must be a better way than this and I would be surprised if
>> there isn't already something out there in a library but I haven't found
>> anything yet. Any help here would be great.
>>
>> Thanks,
>>
>> --
>> Paulo Matos
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "Racket Users" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to racket-users+unsubscr...@googlegroups.com.
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/racket-users/87r1icxuhi.fsf%40linki.tools.
--
Paulo Matos
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Re: [racket-users] Redirecting shared lib stdout
Can you use BinaryenModuleWriteText instead? It looks like it was
added to address your use case. -J
On Wed, May 12, 2021 at 3:49 AM Paulo Matos wrote:
>
> Hi,
>
> I have a shared library for which I am creating some bindings:
> https://github.com/pmatos/racket-binaryen
>
> There's a function BinaryenModulePrint that prints a WebAssembly module
> to stdout.
>
> When I wrap it in racket, if I do something like:
> (define mod ...)
> (with-output-to-string (lambda () (BinaryenModulePrint mod)))
>
> The return value will be "" and it will still print the module to
> stdout. I understand! However, I don't know how to solve it in Racket.
>
> In C, things seem easier because I have access to dup2 and pipe in case
> I need to redirect things, however in Racket all my attempts have
> failed.
>
> I have created the simple example:
> ```hello.c
> #include
>
> void hello(void) {
> printf("hello world!\n");
> }
> ```
>
> Compile with `gcc -shared -o hello.so hello.c`.
>
> Then:
> ```hello.rkt
> #lang racket/base
>
> (require racket/port
> ffi/unsafe
> ffi/unsafe/define)
>
> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
> (define-ffi-definer define-hello libhello)
> (define-hello hello (_fun -> _void))
> (with-output-to-string hello)
> ```
>
> Here's the issue! In C, I can do something like:
> ```hello-fix.c
> #include
> #include
> #include
> #include
>
> extern void hello(void);
>
> int main(void) {
> int filefd = open("test.txt", O_WRONLY|O_CREAT, 0666);
> dup2(filefd, fileno(stdout));
> hello();
>
> return 0;
> }
> ```
> Compile with `gcc -o hello hello.c hello-fix.c`
>
> This will, send the output of hello() to a file. Now, in racket
> preferably I want to connect what is sent to raw stdout, fd 1, to
> current-output-port.
>
> My thought was that I could create a dup2 ffi binding, and use
> unsafe-port->file-descriptor to install the racket pipe file descriptor
> in stdout using the dup2 ffi binding but it doesn't work.
>
> And it doesn't work because the unsafe-port->file-descriptor returns #f,
> even though port-waiting-peer? return #f as well (which sort of hints
> that maybe the documentation of unsafe-port->file-descriptor is
> incomplete.
>
> The start of my attempt would look like this:
>
> ```hello.rkt
> #lang racket/base
>
> (require racket/port
> ffi/unsafe
> ffi/unsafe/define
> ffi/unsafe/port)
>
> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>
> (define-ffi-definer define-libc (ffi-lib #f))
> (define-ffi-definer define-hello libhello)
>
> (define-libc dup2 (_fun _int _int -> _int))
> (define-hello hello (_fun -> _void))
>
> (define-values (in out) (make-pipe))
>
> ;; FAILS because (unsafe-port-> ...) return #f
> (dup2 (unsafe-port->file-descriptor out) 1)
>
> ;;...
> ;; connect the other end of the port to current-output-port
> ;; and use a thread to copy-port
> ```
>
> Surely there must be a better way than this and I would be surprised if
> there isn't already something out there in a library but I haven't found
> anything yet. Any help here would be great.
>
> Thanks,
>
> --
> Paulo Matos
>
> --
> You received this message because you are subscribed to the Google Groups
> "Racket Users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to racket-users+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/racket-users/87r1icxuhi.fsf%40linki.tools.
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Re: [racket-users] Redirecting shared lib stdout
I ran into this issue with rsound. I'm not sure how standard output can
be directly captured from a lower-level language in a Racket context
when that language can freely ignore the Racket printer and write
directly to STDOUT within the same operating system process.
I'd hate to just add a "me too", but the only way quick way I could
think to handle that was to add another subprocess. If I were wanting to
solve the problem in one process, I'd probably extend Racket at the C
level and integrate my output with ports.
https://docs.racket-lang.org/inside/Ports_and_the_Filesystem.html?q=c%20api
On 5/12/21 3:48 AM, Paulo Matos wrote:
> Hi,
>
> I have a shared library for which I am creating some bindings:
> https://github.com/pmatos/racket-binaryen
>
> There's a function BinaryenModulePrint that prints a WebAssembly module
> to stdout.
>
> When I wrap it in racket, if I do something like:
> (define mod ...)
> (with-output-to-string (lambda () (BinaryenModulePrint mod)))
>
> The return value will be "" and it will still print the module to
> stdout. I understand! However, I don't know how to solve it in Racket.
>
> In C, things seem easier because I have access to dup2 and pipe in case
> I need to redirect things, however in Racket all my attempts have
> failed.
>
> I have created the simple example:
> ```hello.c
> #include
>
> void hello(void) {
>printf("hello world!\n");
> }
> ```
>
> Compile with `gcc -shared -o hello.so hello.c`.
>
> Then:
> ```hello.rkt
> #lang racket/base
>
> (require racket/port
> ffi/unsafe
> ffi/unsafe/define)
>
> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
> (define-ffi-definer define-hello libhello)
> (define-hello hello (_fun -> _void))
> (with-output-to-string hello)
> ```
>
> Here's the issue! In C, I can do something like:
> ```hello-fix.c
> #include
> #include
> #include
> #include
>
> extern void hello(void);
>
> int main(void) {
>int filefd = open("test.txt", O_WRONLY|O_CREAT, 0666);
>dup2(filefd, fileno(stdout));
>hello();
>
>return 0;
> }
> ```
> Compile with `gcc -o hello hello.c hello-fix.c`
>
> This will, send the output of hello() to a file. Now, in racket
> preferably I want to connect what is sent to raw stdout, fd 1, to
> current-output-port.
>
> My thought was that I could create a dup2 ffi binding, and use
> unsafe-port->file-descriptor to install the racket pipe file descriptor
> in stdout using the dup2 ffi binding but it doesn't work.
>
> And it doesn't work because the unsafe-port->file-descriptor returns #f,
> even though port-waiting-peer? return #f as well (which sort of hints
> that maybe the documentation of unsafe-port->file-descriptor is
> incomplete.
>
> The start of my attempt would look like this:
>
> ```hello.rkt
> #lang racket/base
>
> (require racket/port
> ffi/unsafe
> ffi/unsafe/define
> ffi/unsafe/port)
>
> (define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
>
> (define-ffi-definer define-libc (ffi-lib #f))
> (define-ffi-definer define-hello libhello)
>
> (define-libc dup2 (_fun _int _int -> _int))
> (define-hello hello (_fun -> _void))
>
> (define-values (in out) (make-pipe))
>
> ;; FAILS because (unsafe-port-> ...) return #f
> (dup2 (unsafe-port->file-descriptor out) 1)
>
> ;;...
> ;; connect the other end of the port to current-output-port
> ;; and use a thread to copy-port
> ```
>
> Surely there must be a better way than this and I would be surprised if
> there isn't already something out there in a library but I haven't found
> anything yet. Any help here would be great.
>
> Thanks,
>
> --
> Paulo Matos
>
> --
> You received this message because you are subscribed to the Google Groups
> "Racket Users" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to racket-users+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/racket-users/87r1icxuhi.fsf%40linki.tools.
--
~slg
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[racket-users] Redirecting shared lib stdout
Hi,
I have a shared library for which I am creating some bindings:
https://github.com/pmatos/racket-binaryen
There's a function BinaryenModulePrint that prints a WebAssembly module
to stdout.
When I wrap it in racket, if I do something like:
(define mod ...)
(with-output-to-string (lambda () (BinaryenModulePrint mod)))
The return value will be "" and it will still print the module to
stdout. I understand! However, I don't know how to solve it in Racket.
In C, things seem easier because I have access to dup2 and pipe in case
I need to redirect things, however in Racket all my attempts have
failed.
I have created the simple example:
```hello.c
#include
void hello(void) {
printf("hello world!\n");
}
```
Compile with `gcc -shared -o hello.so hello.c`.
Then:
```hello.rkt
#lang racket/base
(require racket/port
ffi/unsafe
ffi/unsafe/define)
(define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
(define-ffi-definer define-hello libhello)
(define-hello hello (_fun -> _void))
(with-output-to-string hello)
```
Here's the issue! In C, I can do something like:
```hello-fix.c
#include
#include
#include
#include
extern void hello(void);
int main(void) {
int filefd = open("test.txt", O_WRONLY|O_CREAT, 0666);
dup2(filefd, fileno(stdout));
hello();
return 0;
}
```
Compile with `gcc -o hello hello.c hello-fix.c`
This will, send the output of hello() to a file. Now, in racket
preferably I want to connect what is sent to raw stdout, fd 1, to
current-output-port.
My thought was that I could create a dup2 ffi binding, and use
unsafe-port->file-descriptor to install the racket pipe file descriptor
in stdout using the dup2 ffi binding but it doesn't work.
And it doesn't work because the unsafe-port->file-descriptor returns #f,
even though port-waiting-peer? return #f as well (which sort of hints
that maybe the documentation of unsafe-port->file-descriptor is
incomplete.
The start of my attempt would look like this:
```hello.rkt
#lang racket/base
(require racket/port
ffi/unsafe
ffi/unsafe/define
ffi/unsafe/port)
(define libhello (ffi-lib "/home/pmatos/dev/tmp/ffi-hello-world/hello.so"))
(define-ffi-definer define-libc (ffi-lib #f))
(define-ffi-definer define-hello libhello)
(define-libc dup2 (_fun _int _int -> _int))
(define-hello hello (_fun -> _void))
(define-values (in out) (make-pipe))
;; FAILS because (unsafe-port-> ...) return #f
(dup2 (unsafe-port->file-descriptor out) 1)
;;...
;; connect the other end of the port to current-output-port
;; and use a thread to copy-port
```
Surely there must be a better way than this and I would be surprised if
there isn't already something out there in a library but I haven't found
anything yet. Any help here would be great.
Thanks,
--
Paulo Matos
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