ted@ultra.com (Ted Schroeder) (01/05/90)
I have a macro that needs to turn an argument into a character string.
I notice in IBM/370 C there is a # operator that will do just this.
Is this proper ANSI C?
Here's an example:
#define PRINTS(a) printf("%s\n", #a);
Also, I would like to create an integer that is full of '+' characters
i.e. on an ASCII machine the four byte integer would be 0x2b2b2b2b.
Unfortunately the code must run on both ASCII and EBCDIC machines.
Right now I do the following
#ifdef ASCII
#define PLUS 0x2b2b2b2b
#else /* EBCDIC */
#define PLUS 0x4e4e4e4e
#endif /* ASCII */
Is there any portable way to do this?
Thanks in advance for your help.
Ted Schroeder ted@Ultra.com
Ultra Network Technologies ...!ames!ultra!ted
101 Daggett Drive
San Jose, CA 95134
408-922-0100
Disclaimer: I don't even believe what I say, why should my company?barmar@think.com (Barry Margolin) (01/05/90)
In article <1990Jan4.190431.19748@ultra.com> ted@ultra.com (Ted Schroeder) writes: >Also, I would like to create an integer that is full of '+' characters >i.e. on an ASCII machine the four byte integer would be 0x2b2b2b2b. >Unfortunately the code must run on both ASCII and EBCDIC machines. >Is there any portable way to do this? I don't think this can be done fully portably, because you can't assume that integers and chars are 32 and 8 bits wise, respectively. If you're will to be portably only to such systems (which is better than your previous solution), I think the following will do it: '+'<<24 | '+'<<16 | '+'<<8 | '+' You could also create a union of an integer and a four-character array full of '+' characters. This also isn't truly portable, but it will also work on many systems. -- Barry Margolin, Thinking Machines Corp. barmar@think.com {uunet,harvard}!think!barmar
karl@haddock.ima.isc.com (Karl Heuer) (01/07/90)
In article <1990Jan4.190431.19748@ultra.com> ted@ultra.com (Ted Schroeder) writes: >I would like to create an integer that is full of '+' characters >i.e. on an ASCII machine the four byte integer would be 0x2b2b2b2b. >Unfortunately the code must run on both ASCII and EBCDIC machines. First I'll mention the siamese character constant '++++', but only to disrecommend it. It'll probably give you the right answer, but you can't count on the compiler accepting it without a warning. Barry suggested ('+'<<24 | '+'<<16 | '+'<<8 | '+'); the briefer form (0x01010101 * '+') is equivalent. You can eliminate the byte- and word-size assumptions with the following (note that the result is cast-free, and hence usable at the preprocessor level, only if the compiler is ANSI): #if __STDC__ #include <limits.h> #else #define UINT_MAX (~(unsigned int)0) #define UCHAR_MAX ((unsigned char)UINT_MAX) #endif #define PLUS (UINT_MAX / UCHAR_MAX * '+') Karl W. Z. Heuer (karl@haddock.isc.com or ima!haddock!karl), The Walking Lint