RHS 15Nov2004
A sprintf-like command that returns a Tcl_Obj. I use it to do things like:
Tcl_ListObjAppendElement(interp, bcListObj, RHS_MakeStringObj("The offset: %d", pcOffset));I'm sure there's places in the code that would run into problems when not using gcc, but thats all I use. If people want to improve this, that would be fantastic. Now, for the actual code...
// This is coded specifically for glibc
Tcl_Obj *
RHS_MakeStringObj(const char *fmt, ...) {
/* Guess we need no more than 100 bytes. */
int n, size = 100;
char *p;
Tcl_Obj *retObj;
va_list ap;
if ((p = Tcl_Alloc (size)) == NULL)
return (Tcl_Obj *)NULL;
while (1) {
/* Try to print in the allocated space. */
va_start(ap, fmt);
n = vsnprintf (p, size, fmt, ap);
va_end(ap);
/* If that worked, return the string. */
if (n > -1 && n < size) {
retObj = Tcl_NewStringObj(p, strlen(p));
Tcl_Free(p);
return retObj;
}
/* Else try again with more space. */
if (n > -1) /* glibc 2.1 */
size = n+1; /* precisely what is needed */
else /* glibc 2.0 */
size *= 2; /* twice the old size */
if ((p = Tcl_Realloc (p, size)) == NULL) {
return (Tcl_Obj *)NULL;
}
}
}RHS It appears that the microsoft compiler uses the name _vsnprintf rather than vsnprintf. So, if you're using MSVC, you may need to change the name.
From chat:
<patthoyts> In fact, on BSD it looks like you need stdio.h and stdarg.h
MAK Since you mention gcc, I suggest:
#ifndef __GNUC__ # define __attribute__(x) #endif Tcl_Obj * RHS_MakeStringObj(const char *fmt, ...) __attribute__((format(printf, 1, 2)))) ...
This tells gcc that the form of the arguments is the same as a printf and that it should check to make sure that the number of arguments and their types are appropriate given the format string, and issue errors/warnings if not, just as if you mess up a printf() call.