Section: libcurl Manual (3)
Updated: June 25, 2020
curl_easy_escape - URL encodes the given string
char *curl_easy_escape( CURL *curl, const char *string
, int length );
This function converts the given input string
to a 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 length is set to 0 (zero), curl_easy_escape(3) uses strlen() on
the input string to find out the size.
You must curl_free(3) the returned string when you're done with it.
libcurl is typically not aware of, nor does it care about, character
encodes the data byte-by-byte into the
URL encoded version without knowledge or care for what particular character
encoding the application or the receiving server may assume that the data
The caller of curl_easy_escape(3) must make sure that the data passed in
to the function is encoded correctly.
Added in 7.15.4 and replaces the old curl_escape(3)
A pointer to a null-terminated string or NULL if it failed.
CURL *curl = curl_easy_init();
char *output = curl_easy_escape(curl, "data to convert", 15);
printf("Encoded: %s\n", output);