FIX: istream::operator>>(long&) Does Not Clear errno

MORE INFORMATION

Sample Code

/*
The following sample code demonstrates only the bug and workaround, not
normal error checking.

Compile options needed: none
*/ 

#include    <iostream.h>
#include    <strstrea.h>
#include    <stdio.h>
#include    <stdlib.h>
#include    <string.h>
#define     MAX_STRING_LEN      100
//#define     CLEAR_ERRNO    // uncomment to work around bug

void main()
{
    char    dc1a, dc1b, dc2a, dc2b;
    long    input1a=0, input1b=0;
    long    input2a=0, input2b=0;
    char    szTest1[MAX_STRING_LEN];
    char    szTest2[MAX_STRING_LEN];

    strcpy(szTest1,"a2147483648z50"); // 
    strcpy(szTest2,"a500z50");

    istrstream    StrStream1(szTest1); //String stream 1
    istrstream    StrStream2(szTest2); //String stream 2

    //    The following command will fail since value input to
    //    input1a=2147483648 is
    //    bigger that maximum value long can hold.

    StrStream1 >> dc1a >> input1a >> dc1b >> input1b;
#ifdef    CLEAR_ERRNO
    errno = 0;
#endif
    StrStream2 >> dc2a >> input2a >> dc2b >> input2b;

    cout << "\n    dc1a: " << dc1a
         << "\n input1a: " << input1a
         << "\n    dc1b: " << dc1b
         << "\n input1b: " << input1b << endl;

    cout << "\n    dc2a: " << dc2a
         << "\n input2a: " << input2a
         << "\n    dc2b: " << dc2b
         << "\n input2b: " << input2b << endl;

    cout << "\n\nPress any key to continue..." << endl;
    dc1a = getchar();
}

/*
The output is:
    dc1a: a
 input1a: 2147483647
    dc1b:
 input1b: 0

    dc2a: a
 input2a: 500
    dc2b:
 input2b: 0

If CLEAR_ERRNO is set, the output is as expected:
    dc1a: a
 input1a: 2147483647
    dc1b:
 input1b: 0

    dc2a: a
 input2a: 500
    dc2b: z
 input2b: 50
*/