[Bug c++/32730] New: std::string.find(x, std::string::npos) searchs from begining of string

["gnu at bluedreamer dot com" <gcc-bugzilla at gcc dot gnu dot org>]

string.find returns results when it should not:

x=4294967295 Found:a test
x=4294967294 Found:a test
x=4294967293 Found:a test
x=4294967292 Not found
x=4294967291 Not found
x=4294967290 Not found
x=4294967289 Not found
x=4294967288 Not found
x=4294967287 Not found
x=4294967286 Not found

Also happens on gcc4.1.2 FreeBSD gcc2.95.2 Unixware 7.1 and gcc4.1.1 Linux 64


[~]$ g++ -v --save-temps -Wall -ansi -pedantic str3.cpp
Using built-in specs.
Target: i386-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--enable-checking=release --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-libgcj-multifile
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk
--disable-dssi --enable-plugin
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre --with-cpu=generic
--host=i386-redhat-linux
Thread model: posix
gcc version 4.1.1 20070105 (Red Hat 4.1.1-52)
 /usr/libexec/gcc/i386-redhat-linux/4.1.1/cc1plus -E -quiet -v -D_GNU_SOURCE
str3.cpp -mtune=generic -ansi -Wall -pedantic -fpch-preprocess -o str3.ii
ignoring nonexistent directory
"/usr/lib/gcc/i386-redhat-linux/4.1.1/../../../../i386-redhat-linux/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/i386-redhat-linux/4.1.1/../../../../include/c++/4.1.1

/usr/lib/gcc/i386-redhat-linux/4.1.1/../../../../include/c++/4.1.1/i386-redhat-linux
 /usr/lib/gcc/i386-redhat-linux/4.1.1/../../../../include/c++/4.1.1/backward
 /usr/local/include
 /usr/lib/gcc/i386-redhat-linux/4.1.1/include
 /usr/include
End of search list.
 /usr/libexec/gcc/i386-redhat-linux/4.1.1/cc1plus -fpreprocessed str3.ii -quiet
-dumpbase str3.cpp -mtune=generic -ansi -auxbase str3 -Wall -pedantic -ansi
-version -o str3.s
GNU C++ version 4.1.1 20070105 (Red Hat 4.1.1-52) (i386-redhat-linux)
        compiled by GNU C version 4.1.1 20070105 (Red Hat 4.1.1-52).
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: aa6f91b930c2d3bef702d56afc079b20
 as -V -Qy -o str3.o str3.s
GNU assembler version 2.17.50.0.6-2.el5 (i386-redhat-linux) using BFD version
2.17.50.0.6-2.el5 20061020
 /usr/libexec/gcc/i386-redhat-linux/4.1.1/collect2 --eh-frame-hdr -m elf_i386
--hash-style=gnu -dynamic-linker /lib/ld-linux.so.2
/usr/lib/gcc/i386-redhat-linux/4.1.1/../../../crt1.o
/usr/lib/gcc/i386-redhat-linux/4.1.1/../../../crti.o
/usr/lib/gcc/i386-redhat-linux/4.1.1/crtbegin.o
-L/usr/lib/gcc/i386-redhat-linux/4.1.1 -L/usr/lib/gcc/i386-redhat-linux/4.1.1
-L/usr/lib/gcc/i386-redhat-linux/4.1.1/../../.. str3.o -lstdc++ -lm -lgcc_s
-lgcc -lc -lgcc_s -lgcc /usr/lib/gcc/i386-redhat-linux/4.1.1/crtend.o
/usr/lib/gcc/i386-redhat-linux/4.1.1/../../../crtn.o

#include <iostream>
#include <string>
#include <climits>

int main(int argc, char *argv[])
{
   std::string a("this is a test");

   std::string b("a t");

   for(unsigned long x=ULONG_MAX; x>ULONG_MAX-10; --x)
   {
      std::string::size_type y=a.find(b, x);

      if(y==std::string::npos)
      {
         std::cout << "x=" << x << " Not found\n";
      }
      else
      {
         std::cout << "x=" << x << " Found:" << a.substr(y) << std::endl;
      }
   }

   return 0;
}


-- 
           Summary: std::string.find(x, std::string::npos) searchs from
                    begining of string
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gnu at bluedreamer dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32730