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From: "vincent-srcware at vinc17 dot net" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug stdio/30647] New: scanf functions wrong on nan() Date: Mon, 17 Jul 2023 15:30:06 +0000 [thread overview] Message-ID: <bug-30647-131@http.sourceware.org/bugzilla/> (raw) https://sourceware.org/bugzilla/show_bug.cgi?id=30647 Bug ID: 30647 Summary: scanf functions wrong on nan() Product: glibc Version: 2.37 Status: UNCONFIRMED Severity: normal Priority: P2 Component: stdio Assignee: unassigned at sourceware dot org Reporter: vincent-srcware at vinc17 dot net Target Milestone: --- On a string input containing "nan()" with parentheses (possibly with n-char-sequence), the scanf functions assume that the subject sequence is just "nan". Note that strtod is correct, i.e. it takes the parentheses into account. Consider the following testcase: #include <stdio.h> #include <stdlib.h> static void test_strtod (const char *s) { char *endptr; double d; printf ("strtod test on %s\n", s); d = strtod (s, &endptr); printf ("d = %g \"%s\"\n", d, endptr); } int main (void) { int r; double a, b, c; test_strtod ("nan*"); test_strtod ("nan()*"); r = sscanf ("nan nan() 1", "%lf%lf%lf", &a, &b, &c); printf ("sscanf return value: %d\n", r); if (r >= 1) printf ("a = %g\n", a); if (r >= 2) printf ("b = %g\n", b); if (r >= 3) printf ("c = %g\n", c); r = fscanf (stdin, "%lf%lf%lf", &a, &b, &c); printf ("fscanf return value: %d\n", r); if (r >= 1) printf ("a = %g\n", a); if (r >= 2) printf ("b = %g\n", b); if (r >= 3) printf ("c = %g\n", c); return 0; } I get the following output with GNU libc 2.31 and 2.37 on Debian: $ printf "nan nan() 1" | ./naninput strtod test on nan* d = nan "*" strtod test on nan()* d = nan "*" sscanf return value: 2 a = nan b = nan fscanf return value: 2 a = nan b = nan instead of strtod test on nan* d = nan "*" strtod test on nan()* d = nan "*" sscanf return value: 3 a = nan b = nan c = 1 fscanf return value: 3 a = nan b = nan c = 1 (as obtained with MacOS X 12.6 and Android 13). -- You are receiving this mail because: You are on the CC list for the bug.
next reply other threads:[~2023-07-17 15:30 UTC|newest] Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-07-17 15:30 vincent-srcware at vinc17 dot net [this message] 2023-07-18 11:55 ` [Bug stdio/30647] " vincent-srcware at vinc17 dot net 2024-04-30 16:42 ` carlos at redhat dot com
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