NAME

regex_sub – Replaces matches of a regular expression in a string

SYNOPSIS

#include <rationl.h>
char* regex_sub(reg_t re, char* input, char* replace);
    

DESCRIPTION

regex_sub() searches maximal substring that the regular expression given as parameter matches in intput and replaces it with the replace value. Returns the result of the remplacement. The return value will need to be freed by the programmer. If no occurence is found the string returned is simply the same and the input string.

re The regular expressions to match against

input The input string to replace from.

replace The string to replace occurences found with.

RETURN VALUE

regex_sub() The input string with the replaced values. If there is no match in the input string, the return value is the same as the input. The return value will need to be freed by the programmer.

EXAMPLES

Program that replaces any version number in a file with the latest one

#include <err.h>
#include <rationl.h>
#include <stdlib.h>
#include <stdio.h>
int main(int argc, char **argv)
{


    if (argc != 2)


        errx(1, "No input file found.");


    reg_t re = regex_compile("v(\\d+)\\.(\\d+)\\.(\\d+)");


    char *line_buf = NULL;


    size_t line_buf_size = 0;


    int line_count = 0;


    ssize_t line_size;


    FILE *fp = fopen(argv[1], "r");


    if (!fp)


    {


        errx(EXIT_FAILURE, "Error opening file '%s'\n", argv[1]);


    }


    char **groups;


    while ((line_size = getline(&line_buf, &line_buf_size, fp) >= 0))


    {


        char* replaced_value = regex_sub(re, line_buf, "v2.5.0");


        printf("old:%snew:%s", line_buf, replaced_value);


        free(replaced_value);


    }


    free(line_buf);


    fclose(fp);


    regex_free(re);


    return 0;
}
    

SEE ALSO

regex_match(3) regex_search(3)