curl_easy_escape(3) Library Functions Manual curl_easy_escape(3)
NAME
curl_easy_escape - URL encode a string
SYNOPSIS
#include <curl/curl.h>
char *curl_easy_escape(CURL *curl, const char *string, int length);
DESCRIPTION
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. This function does not accept input
strings longer than CURL_MAX_INPUT_LENGTH (8 MB).
You must curl_free(3) the returned string when you are done with it.
ENCODING
libcurl is typically not aware of, nor does it care about, character en-
codings. curl_easy_escape(3) 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 uses.
The caller of curl_easy_escape(3) must make sure that the data passed in
to the function is encoded correctly.
URLs
URLs are by definition URL encoded. To create a proper URL from a set of
components that may not be URL encoded already, you cannot just URL en-
code the entire URL string with curl_easy_escape(3), because it then
also converts colons, slashes and other symbols that you probably want
untouched.
To create a proper URL from strings that are not already URL encoded, we
recommend using libcurl's URL API: set the pieces with curl_url_set(3)
and get the final correct URL with curl_url_get(3).
PROTOCOLS
This functionality affects all supported protocols
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
char *output = curl_easy_escape(curl, "data to convert", 15);
if(output) {
printf("Encoded: %s\n", output);
curl_free(output);
}
curl_easy_cleanup(curl);
}
}
HISTORY
Since 7.82.0, the curl parameter is ignored. Prior to that there was
per-handle character conversion support for some old operating systems
such as TPF, but it was otherwise ignored.
AVAILABILITY
Added in curl 7.15.4
RETURN VALUE
A pointer to a null-terminated string or NULL if it failed.
SEE ALSO
curl_easy_unescape(3), curl_url_get(3), curl_url_set(3)
libcurl 2026-07-12 curl_easy_escape(3)
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