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#define _GNU_SOURCE
/* Due to conditional compilation, this is GNU source only if the C library
is GNU.
*/
#include <stdlib.h>
#include <string.h>
#include "nstring.h"
#ifdef __GNUC__
#define HAVE_VASPRINTF 1
#else
#define HAVE_VASPRINTF 0
#endif
void
vasprintfN(const char ** const resultP,
const char * const format,
va_list varargs) {
char * result;
#if HAVE_VASPRINTF
vasprintf(&result, format, varargs);
if (result == NULL)
*resultP = strsol;
else
*resultP = result;
#else
/* We have a big compromise here. To do this right, without a
huge amount of work, we need to go through the variable
arguments twice: once to determine how much memory to allocate,
and once to format the string. On some machines, you can
simply make two copies of the va_list variable in normal C
fashion, but on others you need va_copy, which is a relatively
recent invention. In particular, the simple va_list copy
failed on an AMD64 Gcc Linux system in March 2006.
So instead, we just allocate 4K and truncate or waste as
necessary.
*/
size_t const allocSize = 4096;
result = malloc(allocSize);
if (result == NULL)
*resultP = strsol;
else {
size_t realLen;
vsnprintfN(result, allocSize, format, varargs, &realLen);
if (realLen >= allocSize)
strcpy(result + allocSize - 15, "<<<TRUNCATED");
*resultP = result;
}
#endif
}
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