Replace all matches in pcre2_substitute in C - c

Question

I replace the first occurrence of the match with pcre2_substitute,
#define PCRE2_CODE_UNIT_WIDTH 8
#include <stdio.h>
#include <string.h>
#include <pcre2.h>
int main(int argc, char **argv)
{
PCRE2_SPTR pattern = "(\\d+)";
PCRE2_SPTR subject = "1 something 849 for 993";
PCRE2_SPTR replacement = "XXX";
pcre2_code *re;
int errornumber;
int i;
int rc;
PCRE2_SIZE erroroffset;
PCRE2_SIZE *ovector;
size_t subject_length;
size_t replacement_length = strlen((char *)replacement);
pcre2_match_data *match_data;
subject_length = strlen((char *)subject);
PCRE2_UCHAR output[1024] = "";
PCRE2_SIZE outlen = sizeof(output) / sizeof(PCRE2_UCHAR);
re = pcre2_compile(pattern, PCRE2_ZERO_TERMINATED, 0, &errornumber, &erroroffset, NULL);
if (re == NULL)
{
PCRE2_UCHAR buffer[256];
pcre2_get_error_message(errornumber, buffer, sizeof(buffer));
printf("PCRE2 compilation failed at offset %d: %s\n", (int)erroroffset, buffer);
}
match_data = pcre2_match_data_create_from_pattern(re, NULL);
rc = pcre2_substitute(re, subject, subject_length, 0, 0, match_data, NULL, replacement,
replacement_length, output, &outlen);
printf("Output: %s", output);
return 0;
}
I know that I should repeat pcre2_substitute in a loop for replacing the next match, but I am not sure about the safest way to feed output as the subject of the next step.

Answer 1

You can replace all with a single call to pcre2_substitute using extended option PCRE2_SUBSTITUTE_GLOBAL:
rc = pcre2_substitute(re, subject, subject_length, 0,
PCRE2_SUBSTITUTE_GLOBAL | PCRE2_SUBSTITUTE_EXTENDED,
match_data, NULL, replacement, replacement_length, output, &outlen);