Article ID: 70243
Article Last Modified on 12/1/2003
APPLIES TO
- Microsoft FORTRAN Compiler 4.0
- Microsoft FORTRAN Compiler 4.01
- Microsoft FORTRAN Compiler 4.1
- Microsoft FORTRAN Compiler 5.0
- Microsoft FORTRAN Compiler 5.1
- Microsoft FORTRAN Compiler 4.1
- Microsoft FORTRAN Compiler 5.0
- Microsoft FORTRAN Compiler 5.1
This article was previously published under Q70243
SYMPTOMS
Programs compiled with Microsoft FORTRAN versions 4.0, 4.01, 4.1, and 5.0 that concatenate substrings having a variable for a substring index, can give incorrect results or hang the machine when executed under MS-DOS, or result in a protection violation when executed under OS/2.
CAUSE
The problem is usually observed when the concatenation occurs inside a function call, or inside OPEN or IF statements.
RESOLUTION
To avoid this problem, assign the concatenated expression to a temporary character variable and use the temporary variable in the program.
STATUS
Microsoft has confirmed this to be a problem in FORTRAN versions 4.0, 4.01, 4.1, 5.0, and 5.1. This problem was corrected in FORTRAN PowerStation.
MORE INFORMATION
The following sample programs illustrate the problem:
In an IF Statement
character r*2 /'AA'/
n=0
if ('BBB' .gt. r(1:n+2)//'A') then ! The IF statement should
! cause 'YES' to be printed,
! however 'NO' is printed
! instead.
write (*,*) 'YES'
else
write (*,*) 'NO'
endif
if ('BBB' .gt. r(1:2)//'A') then
write (*,*) 'YES'
else
write (*,*) 'NO'
endif
end
In a Function
character*4 a
character*1 b
a = 'cdef'
b = 'd'
i = len(a)
print *, i
j = index('ab'//a(1:i),b) ! The INDEX function should cause '4'
! to be printed, however other values
! are generated instead.
print *, j
end
Assigning the concatenated expression to a temporary character variable and using the temporary variable in the IF statement or function call will prevent the problem from occurring, as illustrated by the following sample programs:
In an IF Statement
character r*2 /'AA'/
character str*13 ! Declare a temporary variable and
str = r(1:n+2)//'A' ! assign the concatenated expression
! to it.
n = 0
if ('BBB' .gt. str) then ! Use the temporary variable in
! the IF statement.
write (*,*) 'YES'
else
write (*,*) 'NO'
endif
if ('BBB' .gt. r(1:2)//'A') then
write (*,*) 'YES'
else
write (*,*) 'NO'
endif
end
In a Function
character*4 a
character*1 b
character*12 str ! Declare a temporary variable.
a = 'cdef'
b = 'd'
i = len(a)
print *, i
str = 'ab'//a(1:i) ! Assign the concatenated expression
! to the temporary variable.
j = index(str,b) ! Use the temporary variable in the
! index function.
print *, j
end
Additional query words: 5.00
Keywords: kbfix KB70243
