ToString.h File Reference

A general ToStream function that takes printf like arguments and returns a std::string. More...

#include <cpn/common.h>
#include <string>

Include dependency graph for ToString.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions
std::string	ToString (const char *fmt,...)

Detailed Description

A general ToStream function that takes printf like arguments and returns a std::string.

Author

John Bridgman

Definition in file ToString.h.

Function Documentation

std::string ToString	(	const char *	fmt,
			...
	)

Takes arguments like printf and returns a std::string.

Parameters

fmt	format string like printf

Returns

an std::string result

Definition at line 31 of file ToString.cc.

{   
    /* Guess we need no more than 100 bytes. */
    int n, size = 100;
    char *p, *np;
    va_list ap;
    std::string ret = "";
    p = (char*)malloc(size);
    if (p == NULL) {
        return ret;
    }

    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) {
            ret = p;
            free(p);
            return ret;
        }
        /* 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 */
        }
        np = (char*)realloc (p, size);
        if (np == NULL) {
            free(p);
            return ret;
        } else {
            p = np;
        }
    }
}