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/* See LICENSE file for copyright and license details. */
#include "libsimple.h"
extern char *argv0;
void
vweprintf(const char *fmt, va_list ap)
{
int saved_errno = errno, r;
const char *end = strchr(fmt, '\0');
const char *prefix1 = argv0;
const char *prefix2 = ": ";
const char *suffix1 = "";
const char *suffix2 = "";
const char *suffix3 = "";
char *message = NULL;
va_list ap1;
va_list ap2;
if (!argv0 || !strncmp(fmt, "usage: ", strlen("usage: ")))
prefix1 = prefix2 = "";
va_copy(ap1, ap);
va_copy(ap2, ap);
r = vsnprintf(NULL, 0, fmt, ap1);
if (0 <= r && (size_t)r < SIZE_MAX) {
message = alloca((size_t)r + 1);
vsprintf(message, fmt, ap2);
}
va_end(ap2);
va_end(ap1);
if (!*fmt) {
suffix1 = strerror(saved_errno);
suffix2 = "\n";
} else if (end[-1] == ':') {
suffix1 = " ";
suffix2 = strerror(saved_errno);
suffix3 = "\n";
} else if (end[-1] != '\n') {
suffix1 = "\n";
}
if (message) {
/* This is to avoid mangling when multiple processes are writting. */
fprintf(stderr, "%s%s%s%s%s%s", prefix1, prefix2, message, suffix1, suffix2, suffix3);
} else {
fprintf(stderr, "%s%s", prefix1, prefix2);
vfprintf(stderr, fmt, ap);
fprintf(stderr, "%s%s%s", suffix1, suffix2, suffix3);
}
errno = saved_errno;
}
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