From: ori@eigenstate.org
To: qwx@sciops.net, 9front@9front.org
Subject: Re: [9front] libstdio fscanf regression
Date: Thu, 14 May 2020 17:51:47 -0700 [thread overview]
Message-ID: <80954AE3C6C5B7FA9CEE3F96050E744A@eigenstate.org> (raw)
In-Reply-To: <C2203AEDA91A3A95DDC2F8A8755C03FE@wopr.sciops.net>
> Hello,
>
> Commit 7551 (fix '%[]' specifiers and '%n' (thanks phil9)) seems to have
> broken libstdio's *scanf (ape version untested).
>
> Test case is games/doom's configuration file loading, which uses fscanf:
> /sys/src/games/doom/m_misc.c:314
>
> ...
>
> if (fscanf (f, "%79s %[^\n]\n", def, strparm) == 2)
>
> ...
Thanks for the report -- I think this is what we want. At least,
it works for your test case, and it tracks with what I'd expect
the semantics to be. I haven't pored over the spec yet.
Test code:
#include <u.h>
#include <libc.h>
#include <stdio.h>
void
main(int argc, char **argv)
{
char def[80], strparm[128];
print("%d\n", scanf("%79s %[^\n]\n", def, strparm));
exits(nil);
}
Patch:
diff -r 35459627f401 sys/src/ape/lib/ap/stdio/vfscanf.c
--- a/sys/src/ape/lib/ap/stdio/vfscanf.c Wed May 13 18:50:01 2020 -0700
+++ b/sys/src/ape/lib/ap/stdio/vfscanf.c Thu May 14 17:48:32 2020 -0700
@@ -416,7 +416,7 @@
}
if(!match(c, pat)){
nungetc(c, f);
- return 0;
+ return nn > 0;
}
if(store)
*s++=c;
diff -r 35459627f401 sys/src/libstdio/vfscanf.c
--- a/sys/src/libstdio/vfscanf.c Wed May 13 18:50:01 2020 -0700
+++ b/sys/src/libstdio/vfscanf.c Thu May 14 17:48:32 2020 -0700
@@ -339,6 +339,7 @@
int c, nn;
register char *s;
register const char *pat;
+
pat=++fmtp;
if(*fmtp=='^') fmtp++;
if(*fmtp!='\0') fmtp++;
@@ -354,7 +355,7 @@
}
if(!match(c, pat)){
nungetc(c, f);
- return 0;
+ return nn > 0;
}
if(store) *s++=c;
nn++;
next prev parent reply other threads:[~2020-05-15 0:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 0:20 qwx
2020-05-15 0:51 ` ori [this message]
2020-05-15 1:37 ` [9front] " qwx
2020-05-15 1:42 ` ori
2020-05-15 2:06 ` qwx
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