You can also use flex to make a scanner with very little fuss. For example: 

%{
void process(char *tok);
%}

%option noyywrap

%%

[0-9]+     process(yytext);

[ \t\n]+   /* ignore */

.          /* printf("Bad input character: %s\n", yytext); */

%%

void process(char *tok)
{
    printf("%d\n", atoi(tok));
}

int main(int argc, char **argv)
{
    yyin = stdin;

    if (argc > 1)
        yyin = fopen(argv[1], "r");

    return yylex();
}

[download]

Just run it through flex and compile the generated lex.yy.c.

In reply to Re^5: Reading a huge input line in parts by Anonymous Monk
in thread Reading a huge input line in parts by kroach

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