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You are completely overthinking this.


regex_t re;
char file[] = "hello777world99yew 8 I8909do23!";
const char *p = file;
regmatch_t match;

if(regcomp(&re, "[0-9]+", REG_EXTENDED) != 0)...

regexec() will not find multiple instances of your parenthesized expression. There are multiple elements in pmatch because you can have multiple sets of parentheses, not for any other reason.
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