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Yup. With PL/I the maximum length of the string is set when the string is allocated, usually dynamically during execution. The length can be given as a constant in the source code or set from computations during execution. There is also a current length <= the maximum length. When passing that string to a subroutine, the subroutine has to work a little to discover the maximum string length, but, by in effect 'hiding' both the current and maximum length from the programmer of the subroutine, the frequency of some of the errors you mentioned should be reduced. In Visual Basic .NET, the maximum length of any string is the same, as I recall, 2 GB. Then having the strings be 'immutable' was a cute approach, slightly frustrating at times but otherwise quite nice and a good way to avoid the problems you mentioned. But, of course, the way I actually used strings in C was close to the way they were supported in Fortran. And, of course, likely 100,000+ C programmers wrote their own collection of string handling routines where use a struct to keep all the important data on the string, say, allocated or not, pointer to the allocated storage, maximum allocated length, current length, etc. (multi-byte character set anyone?) and then pass just a pointer to the struct instead of a pointer to the storage of the string; in this way, again should reduce the frequency of some of the errors you mentioned. |