curl_unescape(3) Library Functions Manual curl_unescape(3)

curl_unescape - URL decodes the given string

#include <curl/curl.h>
char *curl_unescape(const char *input, int length);

Obsolete function. Use curl_easy_unescape(3) instead.

This function converts the URL encoded string input to a "plain string" and return that as a new allocated string. All input characters that are URL encoded (%XX where XX is a two-digit hexadecimal number) are converted to their plain text versions.

If the length argument is set to 0, curl_unescape(3) calls strlen() on input to find out the size.

You must curl_free(3) the returned string when you are done with it.

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    char *decoded = curl_unescape("%63%75%72%6c", 12);
    if(decoded) {
      /* do not assume printf() works on the decoded data */
      printf("Decoded: ");
      /* ... */
      curl_free(decoded);
    }
  }
}

Since 7.15.4, curl_easy_unescape(3) should be used. This function might be removed in a future release.

A pointer to a null-terminated string or NULL if it failed.

RFC2396, curl_easy_escape(3), curl_easy_unescape(3), curl_free(3)

March 12 2024 libcurl