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May 01, 2005 std.stream.stdin.eof() and pipes - do they work together? | ||||
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Hi, I'm using gdc-0.11 which uses the last version of phobos (the one that comes with dmd 0.121) and have a problem with the following program. (I think this is a problem with phobos and not gdc, which is why I'm posting here, but I may be wrong.) # import std.stream, std.stdio; # # int main() { # char[] s; # while (!std.stream.stdin.eof) { # s = std.stream.stdin.readLine(); # writefln("%s", s); # } # return 0; # } When running the program as "./a.out < somefile" the program correctly copies input to output, but when running the program as "cat somefile | ./a.out" the program aborts with the message "Error: Stream is not seekable". On the other hand, the following C program works without error for both cases. # #include <sys/types.h> # #include <unistd.h> # #include <stdio.h> # # int main() { # char s[32]; # while (!feof(stdin)) { # fgets(s, 32, stdin); # if (!feof(stdin)) { # printf("%s", s); # } # } # return 0; # } Some snooping inside std/stream.d shows that eof() uses the size of a file and the current position in the file, which I imagine wouldn't work with pipes because they aren't seekable. Is there a simple solution to my problem: use eof() and readLine() on std.stream.stdin with pipes, or should I just build my own readLine() out of C functions? Thanks, Jay |
May 01, 2005 Re: std.stream.stdin.eof() and pipes - do they work together? | ||||
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Posted in reply to Jay | Piped streams are busted in 120 and 121. There is a fix sitting in Walter in-box but until that hits the net I'd recommend recompiling phobos with the "assertSeekable" function commented out to be a no-op. The issue is that it turned out piped streams depended on being able to seek on streams marked as seekable==false. sorry for the trouble! -Ben "Jay" <Jay_member@pathlink.com> wrote in message news:d519kh$1ilu$1@digitaldaemon.com... > Hi, > > I'm using gdc-0.11 which uses the last version of phobos (the one that > comes > with dmd 0.121) and have a problem with the following program. (I think > this > is a problem with phobos and not gdc, which is why I'm posting here, but I > may > be wrong.) > > # import std.stream, std.stdio; > # > # int main() { > # > char[] s; > # while (!std.stream.stdin.eof) { > # s = > std.stream.stdin.readLine(); > # writefln("%s", s); > # } > # return 0; > # } > When running the program as "./a.out < somefile" the program correctly > copies > input to output, but when running the program as "cat somefile | ./a.out" > the > program aborts with the message "Error: Stream is not seekable". > > On the other > hand, the following C program works without error for both cases. > > # #include > <sys/types.h> > # #include <unistd.h> > # #include <stdio.h> > # > # int main() { > # char s[32]; > # while (!feof(stdin)) { > # fgets(s, 32, stdin); > # if > (!feof(stdin)) { > # printf("%s", s); > # } > # } > # return 0; > # } > > Some > snooping inside std/stream.d shows that eof() uses the size of a file and > the > current position in the file, which I imagine wouldn't work with pipes > because > they aren't seekable. > > Is there a simple solution to my problem: use eof() and > readLine() on > std.stream.stdin with pipes, or should I just build my own > readLine() out of C > functions? > > Thanks, > Jay > > |
May 01, 2005 Re: std.stream.stdin.eof() and pipes - do they work together? | ||||
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Posted in reply to Ben Hinkle | In article <d51auc$1jmo$1@digitaldaemon.com>, Ben Hinkle says... > >Piped streams are busted in 120 and 121. There is a fix sitting in Walter >in-box but until that hits the net I'd recommend recompiling phobos with the >"assertSeekable" function commented out to be a no-op. The issue is that it turned out piped streams depended on being able to seek on streams marked as seekable==false. sorry for the trouble! Thanks Ben, It's only a small interruption. Jay |
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