curl\_easy\_escape(3) Library Functions Manual curl\_easy\_escape(3)

# [NAME](#NAME)

curl\_easy\_escape - URL encode a string

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
char *curl_easy_escape(CURL *curl, const char *string, int length);
```

# [DESCRIPTION](#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). Although not constrained by its type, the returned string may not be altered.

If *length* is set to 0 (zero), [*curl\_easy\_escape(3)*](/man/os/curl/curl_easy_escape.3) uses strlen() on the input *string* to find out the size.

You must [*curl\_free(3)*](/man/os/curl/curl_free.3) the returned string when you are done with it.

# [ENCODING](#ENCODING)

libcurl is typically not aware of, nor does it care about, character encodings. [*curl\_easy\_escape(3)*](/man/os/curl/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)*](/man/os/curl/curl_easy_escape.3) must make sure that the data passed in to the function is encoded correctly.

# [URLs](#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 URL encode the entire URL string with [*curl\_easy\_escape(3)*](/man/os/curl/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)*](/man/os/curl/curl_url_set.3) and get the final correct URL with [*curl\_url\_get(3)*](/man/os/curl/curl_url_get.3).

# [PROTOCOLS](#PROTOCOLS)

This functionality affects all supported protocols

# [EXAMPLE](#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](#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](#AVAILABILITY)

Added in curl 7.15.4

# [RETURN VALUE](#RETURN_VALUE)

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

# [SEE ALSO](#SEE_ALSO)

[**curl\_easy\_unescape**(3)](/man/os/curl/curl_easy_unescape.3), [**curl\_url\_get**(3)](/man/os/curl/curl_url_get.3), [**curl\_url\_set**(3)](/man/os/curl/curl_url_set.3)

2026-10-01 libcurl

---

Document: curl_easy_escape(3) from curl 8.22.0-r4 (Chainguard OS)
Source: https://github.com/curl/curl.git