curl_easy_escape (3) - Linux Manuals
curl_easy_escape: URL encodes the given string
NAME
curl_easy_escape - URL encodes the given stringSYNOPSIS
#include <curl/curl.h>char *curl_easy_escape( CURL *curl, char *url, int length );
DESCRIPTION
This function converts the given input string to an URL encoded string and returns that as a new allocated string. All input characters that are not a-z, A-Z, 0-9, '-', '.', '_' or '~' are converted to their "URL escaped" version (%NN where NN is a two-digit hexadecimal number).If the length argument is set to 0 (zero), curl_easy_escape(3) uses strlen() on the input url to find out the size.
You must curl_free(3) the returned string when you're done with it.